Layered film and process for producing layered film

ABSTRACT

A laminated film is provided, in which a laminated layer including at least 50 percent by weight of composition (A) and cross-linking agent (B) is laminated on at least one surface of a thermoplastic resin film, wherein the composition (A) is a composition comprising a polythiophene and a polyanion or a composition comprising a polythiophene derivative and a polyanion, and the laminated layer has a sea-island structure in which the cross-linking agent (B) is present in the composition (A). Consequently, a laminated film exhibits an unprecedentedly high level of antistatic property unaffected by changes in humidity, and has excellent transparency, water resistance, and scratch resistance.

TECHNICAL FIELD

This disclosure relates to a laminated film. In particular, it relatesto a laminated film which exhibits a high level of antistatic propertyunaffected by changes in humidity and which has excellent transparency,water resistance, and scratch resistance.

BACKGROUND ART

Thermoplastic resin films, e.g., polyolefin films, polyester films,polyamide films, and polyphenylene sulfide films, are widely used asbase films for various purposes, e.g., industrial material uses,magnetic material uses, and packaging uses, because of light weights,small thicknesses, and excellent mechanical properties. Furthermore, inaccordance with the trend toward lighter weight, smaller thickness, andfurther miniaturization, demand for the film is expected to grow invarious areas.

Most of all, biaxially oriented polyester films have excellentproperties with respect to the dimensional stability, mechanicalproperties, thermal resistance, electrical properties, and the like, andtherefore, are widely used as base films for many purposes, for example,magnetic materials, e.g., magnetic tapes typified by VHS tapes,audiotapes, and backup tapes of computer data and cards, such as prepaidcards, IC cards, and optical recording cards; packaging materials;electrically insulating materials; various photographic materials;graphic arts materials; and label materials.

However, since the polyester is an insulating resin, in general, thereis a problem in that biaxially oriented polyester films have noantistatic property unless being further treated. As a result, dusttends to settle on the biaxially oriented polyester film if no treatmentis performed, and products composed of the biaxially oriented polyesterfilm tend to become into intimate contact with each other due toelectrification, so that ease of handling is deteriorated. Furthermore,electrostatic problems occur in that, for example, an electric shock andexplosion occur due to electrostatic discharge, and precision electroniccircuit material elements and the like are broken due to electrostaticdischarge.

Consequently, researches have been previously conducted in order toimpart the antistatic property to polyester films by various methods.

Examples of known methods for preventing electrification includeincorporation of an antistatic agent into a base film and impartation ofan antistatic property to a base film surface. For example, methods inwhich a polyester resin is mixed with an antistatic agent and isapplied, as described in Japanese Unexamined Patent ApplicationPublication No. 60-141525 and the like, and methods in which a styrenesulfonic acid copolymer is applied, as described in Japanese UnexaminedPatent Application Publication No. 61-204240 and the like, are methodsfor preventing electrification through the use of ionic conduction typeantistatic agents. In these methods, an electrical conduction mechanismdepending on adsorption of water in air due to ions is used and,therefore, these methods have dependence on humidity. In particular, thehumidity dependence is significant when a low-molecular weight typeantistatic agent is used and, therefore, with respect to the productquality, serious problems occur in that, for example, no antistaticproperty is attained under an environment in which the humidity is lowas in winter and the like.

In methods described in Japanese Unexamined Patent ApplicationPublication No. 7-101016, Japanese Unexamined Patent ApplicationPublication No. 7-330901, and the like, a layer of a polyaniline-basedconductive agent is provided on a surface of a polyester film, and thepolyaniline-based conductive agent to be used is an electron conductiontype antistatic agent. The conduction mechanism thereof is based onconjugated electrons and, therefore, has no dependence on humidity.However, the polyaniline-based conductive agent is green in thecondition of being subjected to doping, and there are problems in that,for example, an outward appearance of a product is not preferable, anduses are restricted.

In methods described in Japanese Unexamined Patent ApplicationPublication No. 9-152723, Japanese Unexamined Patent ApplicationPublication No. 11-278582, Japanese Unexamined Patent ApplicationPublication No. 7-329250, and the like, a layer of tin oxide-basedconductive agent doped with antimony is provided on a polyester filmsurface. These are methods for preventing electrification through theuse of an electron conduction type antistatic agent. The conductionmechanism thereof is based on conjugated electrons and, therefore, hasno dependence on humidity. However, in order to exhibit theconductivity, the tin oxide-based antistatic agent is in need of adoping agent containing a hazardous heavy metal, e.g., antimony.Furthermore, when a granular antistatic agent typified by the tinoxide-based antistatic agent is applied to an in-line coating method inwhich coating, stretching, and a heat treatment are performed during afilm formation step, no follow-up property to stretching is exhibitedand, therefore, problems occur in that, for example, cracks occur in thecoating film due to stretching, the coating film is whitened or thecoating film becomes brittle, and no scratch resistance is exhibited.

In methods for preventing electrification through the use of otherelectron conduction type antistatic agents described in JapaneseUnexamined Patent Application Publication No. 1-313521, JapaneseUnexamined Patent Application Publication No. 6-295016, and the like,impartation of the antistatic property by a polythiophene-basedconductive agent is proposed. However, an adequate antistatic propertyis not attained by, for example, a method for preventing electrificationin which a coating solution containing the polythiophene-basedconductive agent and a latex polymer is applied. In order to exhibit ahigh level of antistatic property, large amounts of polythiophene-basedconductive agent must be added. Consequently, when this method isapplied to the in-line coating method, there are problems in that thecoating film has significantly poor transparency, and the coating filmis whitened, in a manner similar to that in other electron conductiontype antistatic agents. Therefore, this method is not worthy ofpractical use.

Protective films will be described below.

In recent years, the changeover from so-called cathode-ray tubetelevisions to liquid crystal displays have been actively pursued inaccordance with a revolution in displays. In particular, with respect tothe liquid crystal display, there are steps of processing and mountingof optical sheets, e.g., polarizers, serving as primary constituents,and a protective film is used in order to protect a surface. An adhesiveand the like is applied to or laminated on a transparent film, e.g., apolyethylene film, a polypropylene film, or a polyester film, which isused for protection, in order to bond the film together with an opticalsheet, e.g., a polarizer. The resulting film is used as the protectivefilm.

After mounting of a liquid crystal display and the like is completed,the protective film is peeled and removed. When the protective film ispeeled, a so-called peeling electrification phenomenon occurs, and thereis a problem of adhesion of dirt due to static electricity. If dirt isadhered due to static electricity, for example, it is difficult todiscriminate between defects of a liquid crystal component itself anddefects due to dirt adhered to the surface with respect to theinspection of products, and the inspection is not conducted smoothly. Asa result, significant problems occur in the manufacturing process. Inparticular, with respect to recent high-precision display and the like,besides the problem of the adhesion of dirt due to static electricity, aproblem of breakage of electronic elements of a display occurs due topeeling electrification.

On the other hand, a protective film prepared by incorporating anantistatic agent to a polyethylene film or a polypropylene film has lowtransparency. Since the transparency of the protective film is poor,there are problems in that, for example, the inspection accuracy isdeteriorated in the inspection of defects of products after a liquidcrystal display and the like are mounted, and the inspection takes muchtime.

With respect to even a protective film made of a polyester film havingexcellent transparency, a non-treated film has no antistatic propertyand, therefore, many troubles, e.g., adhesion of dirt, occur due toelectrification. In order to overcome this, researches have beenconducted on a polyester film incorporating an antistatic agent and apolyester film coated with an antistatic agent. However, anysatisfactory film has not been achieved.

Furthermore, cover tapes and carrier packages will be described.

In recent years, surface-mounting chip-shaped electronic components,e.g., ICs (integrated circuits), transistors, diodes, and capacitors,are packaged with a carrier package composed of a carrier tapesuccessively provided with pockets or the like adjusted to the shape ofthe electronic components by embossing in order to store them and acover tape sealing the carrier tape through heat seal or an adhesive,the carrier package is taken up into the shape of a reel, and issupplied.

When the surface-mounting chip-shaped electronic components are used inpractice, they are carried, while being in the state of the reel, to amanufacturing step in which the surface-mounting chip-shaped electroniccomponents are used, and products are manufactured continuously on aproduction line while the cover tape is peeled off the carrier package,in which the carrier tape is sealed with the cover tape, and theelectronic components are taken out.

When the cover tape is peeled off, problems occur in that the electroniccomponents are accidentally released and the electronic components arescattered or that discharge occurs between an electrified tape and anelectronic component and the electronic component is electricallybroken.

Beside the peeling electrification, in a step of storing an electroniccomponent in a carrier tape, followed by sealing, it is known that aphenomenon of frictional electrification occurs due to friction betweenthe electronic component and a carrier roll, a heating bar used for heatseal, and the like. Since the surface-mounting chip-shaped electroniccomponent is a small electronic component, for example, in the casewhere the winding is performed into the shape of a reel having a verysmall width on the order of 5 mm and a length on the order of severalthousand meters, if the frictional electrification phenomenon occurs,problems come up, wherein straying occurs and, thereby, the winding intothe shape of a reel cannot be smoothly performed, or an electroniccomponent in a stored state is electrically broken, in a manner similarto that in the above-described peeling electrification.

In general, when packaging into the carrier package is completed,inspections of the electronic components are performed from the covertape side, wherein the inspection items includes mixing of differenttypes, bending of lead terminals, error in packing direction of ICchips, and the like. In order to readily perform these inspections, thecover tape is strongly required to have transparency. For example, atransparent polyester film, a transparent polyolefin film, and the like,each having high transparency, have been used directly.

Under the above-described circumstances, research is conducted onimpartation of the antistatic property to the carrier tape side in orderto overcome the electrification problem.

In many cases, various resins, e.g., polystyrene, are used as carriertapes. In order to reduce electrification of the carrier tape itself,for example, carbon or the like serving as an antistatic agent isincorporated, or paper or the like is used as an antistatic agent withrespect to inexpensive types. However, any carrier tape havingsatisfactory performance has not been attained until now.

SUMMARY

A laminated film is a laminated film in which a laminated layercomprising at least 50 percent by weight of composition (A) andcross-linking agent (B) is laminated on at least one surface of athermoplastic resin film, wherein the composition (A) is a compositioncomprising a polythiophene and a polyanion or a composition comprising apolythiophene derivative and a polyanion, and the laminated layer has asea-island structure in which the cross-linking agent (B) is present inthe composition (A).

A method for manufacturing a laminated film comprises the steps ofapplying a coating solution containing a composition (A) and across-linking agent (B) to at least one surface of a thermoplastic resinfilm, and performing drying, stretching and, thereafter, heat-treating,wherein the composition (A) is a composition comprising a polythiopheneand a polyanion or a composition comprising a polythiophene derivativeand a polyanion, and 10 to 85 percent by weight of cross-linking agent(B) is contained in the coating solution.

A laminated film for a protective film is manufactured by a methodcomprising the steps of applying a coating solution containing acomposition (A) and a cross-linking agent (B) to at least one surface ofa thermoplastic resin film, and performing drying, stretching and,thereafter, heat-treating, wherein the composition (A) is a compositioncomprising a polythiophene and a polyanion or a composition comprising apolythiophene derivative and a polyanion, and 25 to 85 percent by weightof cross-linking agent (B) is contained in the coating solution.

A laminated film for a cover tape is manufactured by a method comprisingthe steps of applying a coating solution containing a composition (A)and a cross-linking agent (B) to at least one surface of a thermoplasticresin film, and performing drying, stretching and, thereafter,heat-treating, wherein the composition (A) is a composition comprising apolythiophene and a polyanion or a composition comprising apolythiophene derivative and a polyanion, and 10 to 85 percent by weightof cross-linking agent (B) is contained in the coating solution.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a typical schematic diagram of a “sea-island structure” of alaminated film.

FIG. 2 is a transmission electron micrograph (magnification: 500,000times) of a cross-section of a typical laminated layer of a laminatedfilm.

REFERENCE NUMERALS

1: “island” portion

2: “sea” portion

3: embedding resin layer

4: laminated layer

5: PET film

DETAILED DESCRIPTION

In a laminated film, a laminated layer comprising at least 50 percent byweight of composition (A) and cross-linking agent (B) is laminated,wherein the composition (A) is a composition comprising a polythiopheneand a polyanion or a composition comprising a polythiophene derivativeand a polyanion, and the laminated layer has a sea-island structure inwhich the cross-linking agent (B) is present in the composition (A).

The sea-island structure of the laminated film will be described.

The sea-island structure is identified by a transmission electronmicroscope (hereafter abbreviated as “TEM”) observation image of a crosssection of a laminated layer. With respect to a mixed phase including atleast two components, the sea-island structure is composed of a “sea”portion made of a component forming a continuous phase and “island”portions made of the other components present in the shape of islands inthe continuous phase. FIG. 1 is a typical schematic diagram showing a“sea-island structure” of a laminated film. In the drawing, blackportions indicate “island” portions, and a continuous white portionother than them correspond to a “sea” portion. In particular, the“island” portions may have various sizes of cross-sectional areas, asshown in the drawing. The shapes of the “island” portions may havevarious cross-sectional shapes, e.g., a circle, an ellipse, andirregular shapes, and are not specifically limited. A portion having theshape in which at least two island portions are joined is also includedin “island” portions.

A TEM observation image of a cross-section of a typical laminated layerof a laminated film is shown in FIG. 2. However, the laminated film isnot limited to them.

FIG. 2 is a TEM observation image under a magnification of 500,000times. A straight line at the lower right of the drawing indicates ascale, and the length shown at the lower right, for example, the lengthof the straight line in FIG. 2, corresponds to 20 nm.

The forms of “island” portions of the laminated film are not limited,and are, for example, circular, substantially circular, elliptical, andin the form in which at least two circular protrusions are joined.

The laminated layer of the laminated film is a laminated layercontaining at least 50 percent by weight of composition (A) andcross-linking agent (B), wherein the composition (A) is a compositioncomposed of a polythiophene and a polyanion or a composition composed ofa polythiophene derivative and a polyanion. That is, the content of thetotal of the composition (A) and the cross-linking agent (B) in thelaminated layer must be at least 50 percent by weight of the entirelaminated layer. Preferably, the total content of the composition (A)and the cross-linking agent (B) in the laminated film is at least 70percent by weight, and more preferably is at least 80 percent by weight.

Preferably, the composition (A) in the laminated layer of the laminatedfilm contains a polythiophene and a polythiophene derivative.

The composition (A) usable for the laminated layer of the laminated filmmay be prepared by polymerizing compounds represented by the followingformula 1

and/or the following formula 2

in the presence of polyanions.

In the formula 1, R₁ and R₂ independently represent a hydrogen atom; oran aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or anaromatic hydrocarbon group, each having the carbon number of 1 to 12.Examples thereof include a methyl group, an ethyl group, a propyl group,an isopropyl group, a butyl group, a cyclohexylene group, and a benzenegroup. In the formula 2, n represents an integer of 1 to 4.

In the laminated film, preferably, a polythiophene and/or apolythiophene derivative having a structural formula represented by theformula 2 is used. For example, a preferable compound is represented bythe formula 2, where n=1 (a methylene group), n =2 (an ethylene group),or n=3 (a propylene group). Among them, a compound including an ethylenegroup in which n=2, that is, poly-3,4-ethylenedioxythiophene, isparticularly preferable.

With respect to the laminated film, examples of the polythiophene and/orthe polythiophene derivative include compounds having a structure inwhich substituents are bonded at positions 3 and 4 of a thiophene ringand, furthermore, a compound in which oxygen atoms are bonded to carbonatoms at positions 3 and 4 as described above. With respect to compoundsin which hydrogen atoms or carbon atoms are directly bonded to theabove-described carbon atoms, coating solutions may not readily becomewater-based.

The polyanion in the composition (A) used for the laminated layer of thelaminated film will be described.

The polyanion in the laminated film is an acid polymer in a state of afree acid, and is polymeric carboxylic acid, a polymeric sulfonic acid,a polyvinylsulfonic acid,or the like. Examples of polymeric carboxylicacids include a polyacrrylic acid, a polymethacrylic acid, and apolymaleic acid. Examples of polymeric sulfonic acids include apolystyrenesulfonic acid. In particular, the polystyrenesulfonic acid ismost preferable from the viewpoint of electrical conductivity. A part offree acids may be in the form of neutralized salts.

It is believed that when these polyanions are used in thepolymerization, inherently water-insoluble polythiophene-based compoundsare readily dispersed in water or readily become water-based, and thefunction as an acid also serves the function as a dopant of thepolythiophene-based compound.

The polymeric carboxylic acid and the polymeric sulfonic acid can beused in the form of a copolymer with other copolymerizable monomers,e.g., acrylates, methacrylates, and styrene.

The molecular weights of the polymeric carboxylic acid and the polymericsulfonic acid used as polyanions are not specifically limited. However,preferably, the weight average molecular weight thereof is 1,000 to1,000,000, and more preferably is 5,000 to 150,000 from the viewpoint ofthe stability and the electrical conductivity of the coating solution.Alkali salts and ammonium salts, e.g., lithium salts and sodium salts,may be contained as a part of them at a content within the range inwhich the features are not hindered. With respect to the neutralizedsalts as well, it is known that the equilibrium between apolystyrenesulfonic acid functioning as a very strong acid and anammonium salt shifts to the acid side due to advancement of theequilibrium reaction after neutralization. Consequently, the neutralizedsalts are believed to act as dopants.

Preferably, the polyanion is allowed to excessively present relative tothe polythiophene or the polythiophene derivative on a weight of solidbasis from the viewpoint of the electrical conductivity. Preferably, thepolyanion is more than 1 part by weight and 5 parts by weight or lessrelative to 1 part by weight of the polythiophene and/or thepolythiophene derivative, and more preferably is more than 1 part byweight and 3 parts by weight or less.

The above-described composition (A) can be produced by methods describedin Japanese Unexamined Patent Application Publication No. 6-295016,Japanese Unexamined Patent Application Publication No. 7-292081,Japanese Unexamined Patent Application Publication No. 1-313521,Japanese Unexamined Patent Application Publication No. 2000-6324,European Patent No. 602713, U.S. Pat. No. 5,391,472, and the like,although methods other than them may be adopted.

With respect to the composition (A), for example,3,4-ethylenedioxythiophene is prepared from an alkali metal salt of3,4-dihydroxythiophene-2,5-dicarboxyester as a starting material.Thereafter, potassium peroxodisulfate, iron sulfate, and3,4-ethylenedioxythiophene prepared as described above are introducedinto a polystyrenesulfonic acid aqueous solution, and a reaction iseffected, so that a composition is prepared, in which a polyanion, e.g.,polystyrenesulfonic acid, constitute a complex with a polythiophene,e.g., poly(3,4-ethylenedioxythiophene).

Examples of the cross-linking agent (B) usable for the laminated layerof the laminated film may include melamine-based cross-linking agents,epoxy-based cross-linking agents, aziridine-based cross-linking agents,epoxyamide compounds, titanate-based coupling agents, e.g., titaniumchelate, oxazoline-based cross-linking agents, isocyanate-basedcross-linking agents, methylolurea or alkylolurea-based, andacrylamide-based.

Preferably, the molecular weight of the cross-linking agent (B) is 1,000or less. In particular, when the cross-linking agent (B) is soluble inwater and has a molecular weight of 1,000 or less, the flexibility andthe flowability are exhibited in a stretching step, the follow-upproperty to stretching after drying of a mixture constituting thelaminated layer is enhanced, a whitening phenomenon due to cracks in thecoated layer is reduced, and the transparency is imparted. On the otherhand, for example, if the molecular weight becomes too large, phenomenaof, for example, cracking of the coated layer occurs during stretchingafter application and drying and, thereby, the transparency tends to bereduced. When the molecular weight is controlled at 800 or less, morepreferably at 600 or less, the composition (A) and the cross-linkingagent (B) become further compatible with each other and, thereby, thetransparency is improved.

Preferably, the cross-linking agent (B) is a water-soluble cross-linkingagent because the transparency, antistatic property, and the like areimproved.

A water-soluble cross-linking agent refers to a cross-linking agenthaving a water solubility of at least 80 percent. Here, the “watersolubility” refers to a proportion of the cross-linking agent dissolvedinto water when 10 parts by weight of solid cross-linking agent is putinto 90 parts by weight of water at 23° C. That is, the water solubilityof 80 percent represents the state in which 80 percent by weight of 10parts by weight of cross-linking agent is dissolved into 90 parts byweight of water at 23° C., and the remaining 20 parts by weight ofcross-linking agent is left as the insoluble residue. The watersolubility of 100 percent represents the state in which 10 parts byweight of cross-linking agent used is completely dissolved into 90 partsby weight of water. Preferably, the cross-linking agent (B) has a watersolubility of at least 90 percent, and more preferably has a watersolubility of 100 percent. When the water solubility is high, not onlythe coating solution itself is allowed to become water-based, but alsothe coated layer is allowed to have excellent transparency and anexcellent antistatic property.

The melamine-based cross-linking agent is not specifically limited.Examples of usable compounds include melamine, methylolmelaminederivatives prepared by condensing melamine and formaldehyde, completelyor partially etherified compounds prepared by reacting methylolmelamineand lower alcohol, and mixtures thereof. In addition, monomers,condensates composed of dimers or other multimers, mixtures thereof, andthe like may be used as the melamine-based cross-linking agent. Examplesof lower alcohol usable for etherification include methyl alcohol, ethylalcohol, isopropyl alcohol, n-butanol and isobutanol. Examples offunctional groups include imino type methylated melamine, methylol typemelamine, methylol type methylated melamine, and complete alkyl typemethylated melamine, each has an imino group, a methylol group, or analkoxymethyl group, e.g., a methoxymethyl group or a butoxymethyl group,in a molecule. Among them, imino type melamine and methylolmelamine arepreferable, and methylol type melamine is more preferable. Awater-soluble melamine-based cross-linking agent is most preferable and,for example, methylol type melamine may be suitable for use. In order toaccelerate heat curing of the melamine-based cross-linking agent, forexample, an acid catalyst, e.g., p-toluenesulfonic acid, may be used.More preferably, a coating solution itself to be applied is an acidsolution. Since a polyanion, preferably, polystyrenesulfonic acid isused as the cross-linking agent (B), the above-described cross-linkingreaction is accelerated.

An epoxy-based cross-linking agent is particularly preferable as thecross-linking agent (B). The epoxy-based cross-linking agent givesextremely excellent transparency and antistatic property and, thereby,the coated layer can has an excellent coating appearance. Amongepoxy-based cross-linking agents, water-soluble epoxy cross-linkingagents are further suitable.

The epoxy-based cross-linking agents are suitable because they do notcause blocking compared with addition of, for example, a high-boilingpoint solvent, e.g., glycerin, so that no contamination occur in theinside of a tenter used in a heat treatment step, nor occurs airpollution.

With respect to the laminated film, the type of the epoxy-basedcross-linking agent is not specifically limited. Usable agents may be ofsorbitol polyglycidyl ether-based, polyglycerol polyglycidylether-based, diglycerol polyglycidyl ether-based, polyethylene glycoldiglycidyl ether-based, or the like. Examples of suitable agents mayinclude an epoxy compound “DANACOL” (EX-611, EX-614, EX-614B, EX-512,EX-521, EX-421, EX-313, EX-810, EX-830, EX-850, and the like) producedby Nagase ChemteX Corporation, diepoxy and polyepoxy-based compounds(SR-EG, SR-8EG, SR-GLG, and the like) produced by SAKAMOTO YAKUHIN KOGYOCO., LTD., an epoxy cross-linking agent “EPICLON” EM-85-75W or CR-5Lproduced by DAINIPPON INK AND CHEMICALS, INCORPORATED. Among them,water-soluble agents are preferable.

Preferably, the epoxy-based cross-linking agent has a weight per epoxyequivalent of 100 to 300 WPE from the viewpoint of the reactivity, andmore preferably, the weight per epoxy equivalent is 110 to 200 WPE.

Preferably, the coating solution used for manufacturing the laminatedfilm is a water-based coating solution containing water as a primarymedium. For the purposes of improvement in application property,improvement in transparency, and the like, the coating solution used formanufacturing the laminated film may contain an appropriate amount oforganic solvent to the extent that the effects are not hindered.Examples of suitable solvents include isopropyl alcohol, butylcellosolve, ethyl cellosolve, acetone, N-methyl-2-pyrrolidone, ethanol,and methanol. Among them, particularly, isopropyl alcohol is preferablyused from the viewpoint of improvement in application property.Preferably, the content thereof is 20 percent by weight or less in thecoating solution, and more preferably is 10 percent by weight or less.If the coating solution contains large amounts of organic solvent, whenthe coating solution is applied to a so-called in-line coating method,it is undesirable, because there is a risk of explosion in a tenter usedfor performing steps of, for example, preheating, drying, stretching,and a heat treatment.

In the state of a laminated layer, the cross-linking agent (B) of thelaminated film may be in the state of being bonded to a functional groupincluded in a component constituting the laminated layer, may be in theunreacted state, or may be in the state in which cross-linkingstructures are partially formed. In the state of the laminated layer,preferably, the cross-linking agent (B) is in the cross-linking statefrom the viewpoint of the strength of the coated layer, the blockingresistance, the sticky feeling, the water resistance, and the like. Thecross-linking may be in the state in which the cross-linking agent isbonded to a functional group contained in another component, or may hasa self cross-linking structure of the cross-linking agent itself.

Preferably, a plurality of cross-linking agents are used together. Forexample, the combined use of the epoxy-based cross-linking agent and themelamine-based cross-linking agent or the combined use of differenttypes of epoxy-based cross-linking agent is preferable becausecharacteristics of both agents are exhibited.

With respect to the laminated layer of the laminated film, for example,the mixing ratio of the composition (A) and the cross-linking agent (B)is not specifically limited, as long as the laminated layer contains atleast 50 percent by weight of composition (A) and cross-linking agent(B), wherein the composition (A) is a composition comprising apolythiophene and a polyanion or a composition comprising apolythiophene derivative and a polyanion, and the laminated layer has asea-island structure in which the cross-linking agent (B) is present inthe composition (A). However, preferably, 10 to 85 percent by weight ofcross-linking agent (B) is contained in the laminated layer in orderthat the effects are clearly exhibited. For example, if thecross-linking agent (B) is less than 10 percent by weight, theantistatic property may not be readily exhibited. When the content ofthe cross-linking agent (B) is extremely low, the level of insulation issimilar to that of an untreated polyester film and the like, whiteningof the coated layer occurs significantly, and the transparency is poor.On the other hand, if the cross-linking agent (B) exceeds 85 percent byweight, the transparency becomes better, but the antistatic propertyresists may not be exhibited. According to our research, it ispreferable that the content of the cross-linking agent (B) is 25 to 85percent by weight from the viewpoint of the transparency, morepreferably is 25 to 75 percent by weight, and most preferably is 50 to75 percent by weight. When the content of the cross-linking agent (B) inthe laminated layer is controlled at 25 to 75 percent by weight, thetransparency and the antistatic property can become mutually compatibleat an extremely high level.

Preferably, the laminated layer of the laminated film contains apolyester resin in addition to the composition (A) and the cross-linkingagent (B). In the case where a polyester film is used as thethermoplastic resin film, preferably, the polyester resin is containedbecause the adhesion between a base film and the laminated layer isincreased. Other resins, e.g., acrylic resins and urethane resins, maybe used.

The polyester resin suitable as a constituent of the laminated layer ofthe laminated film has an ester bond in a main chain or a side chain,and is produced by polycondensation of dicarboxylic acid and diol.

Examples of carboxylic acid components constituting the polyester resinmay include aromatic, aliphatic, and alicyclic dicarboxylic acids andpolyvalent carboxylic acids of at least trivalent.

Examples of aromatic dicarboxylic acids may include terephthalic acid,isophthalic acid, orthophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid, 1,4-naphthalenedicarboxylic acid,biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid,1,2-bisphenoxyethane-p,p′-dicarboxylic acid, and phenylindandicarboxylicacid. It is preferable to use polyesters in which these aromaticdicarboxylic acids constitute preferably at least 30 mole percent of theentire dicarboxylic acid components, more preferably at least 35 molepercent, and most preferably at least 40 mole percent from the viewpointof the strength and the heat resistance of the laminated layer.

Examples of aliphatic and alicyclic dicarboxylic acids include succinicacid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, dimeracid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylicacid, 1,4-cyclohexanedicarboxylic acid, and ester-forming derivativesthereof.

Examples of glycol components of the polyester resin may includeethylene glycol, diethylene glycol, polyethylene glycol, propyleneglycol, polypropylene glycol, 1,3-propanediol, 1,3-butanediol,1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol,1,8-octanediol, 1,9-nonanediol, 1,10-decanediol,2,4-dimethyl-2-ethylhexane-1,3-diol, neopentyl glycol,2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol,3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,6-hexanediol,1,2-cyclohexane dimethanol, 1,3-cyclohexane dimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 4,4′-thiodiphenol,bisphenol A, 4,4′-methylenediphenol, 4,4′-(2-norbornylidene)diphenol,4,4′-dihydroxybiphenol, o-, m-, and p-dihydroxybenzene,4,4′-isopropylidenephenol, 4,4′-isopropylidenebindiol,cyclopentane-1,2-diol, cyclohexane-1,2-diol, and cyclohexane-1,4-diol.

In the case where a polyester resin is used as a water-based coatingsolution, in order to allow the polyester resin to readily becomesoluble in water or to be readily dispersed in water, preferably,copolymerization with a compound containing a sulfonate group or acompound containing a carboxylate group is performed.

Examples of compounds containing a carboxylate group include trimelliticacid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride,4-methylcyclohexene-1,2,3-tricarboxylic acid, trimesic acid,1,2,3,4-butanetetracarboxylic acid, 1,2,3,4-pentanetetracarboxylic acid,3,3′,4,4′-benzophenonetetracarboxylic acid,5-(2,5-dioxotetrahydrofurfuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylicacid, 5-(2,5-dioxotetrahydrofurfuryl)-3-cyclohexene-1,2-dicarboxylicacid, cyclopentanetetracarboxylic acid,2,3,6,7-naphthalenetetracarboxylic acid,1,2,5,6-naphthalenetetracarboxylic acid, ethylene glycolbistrimellitate, 2,2′,3,3′-diphenyltetracarboxylic acid,thiophene-2,3,4,5-tetracarboxylic acid, ethylenetetracarboxylic acid,alkali metal salts thereof, alkaline-earth metal salts thereof, andammonium salts thereof, although not limited to them.

Examples of compounds containing a sulfonate group may includesulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfoisophthalicacid, 4-sulfonaphthalene-2,7-dicarboxylic acid, sulfo-p-xylylene glycol,2-sulfo-1,4-bis(hydroxyethoxy)benzene, alkali metal salts thereof,alkaline-earth metal salts thereof, and ammonium salts thereof, althoughnot limited to them.

Modified polyester copolymers e.g., block copolymers, graft copolymers,and the like modified by acryl, urethane, epoxy, and the like may beused as the polyester resin.

Examples of preferable polyester resins include copolymers of acidcomponents selected from terephthalic acid, isophthalic acid, sebacicacid, and 5-sodium sulfoisophthalic acid and glycol components selectedfrom ethylene glycol, diethylene glycol, 1,4-butanediol, and neopentylglycol. In the case where the water resistance is required, copolymersin which trimellitic acid is used as a copolymer component in place of5-sodium sulfoisophthalic acid may also be suitable for use.

With respect to the laminated film, the polyester resin used for thelaminated layer may be prepared by the following manufacturing method.

For example, a polyester resin prepared from a dicarboxylic acidcomponent including terephthalic acid, isophthalic acid, and 5-sodiumsulfoisophthalic acid and a glycol component including ethylene glycoland neopentyl glycol will be described. The polyester resin can beprepared by, for example, a method in which terephthalic acid,isophthalic acid, and 5-sodium sulfoisophthalic acid are directlysubjected to an esterification reaction with ethylene glycol andneopentyl glycol, and a method in which terephthalic acid, isophthalicacid, and 5-sodium sulfoisophthalic acid are subjected to atransesterification reaction with ethylene glycol and neopentyl glycolat a first stage, and the reaction product of this first stage issubjected to a polycondensation reaction at a second stage.

At this time, for example, alkali metals, alkaline-earth metals,manganese, cobalt, zinc, antimony, germanium, and titanium compounds maybe used as a reaction catalyst.

Polyester resins including many carboxylic acids at terminals and/or inside chains may be prepared from resins produced by copolymerizationthrough the use of a multivalent carboxylic acid of at least trivalent,as described in Japanese Unexamined Patent Application Publication No.54-46294, Japanese Unexamined Patent Application Publication No.60-209073, Japanese Unexamined Patent Application Publication No.62-240318, Japanese Unexamined Patent Application Publication No.53-26828, Japanese Unexamined Patent Application Publication No.53-26829, Japanese Unexamined Patent Application Publication No.53-98336, Japanese Unexamined Patent Application Publication No.56-116718, Japanese Unexamined Patent Application Publication No.61-124684, Japanese Unexamined Patent Application Publication No.62-240318, and the like. However, methods other than these may beadopted.

The intrinsic viscosity of the polyester resin used for the laminatedlayer of the laminated film is not specifically limited. However,preferably, the intrinsic viscosity is at least 0.3 dl/g, morepreferably is at least 0.35 dl/g, and most preferably is at least 0.4dl/g.

Preferably, the glass transition point (hereafter abbreviated as “Tg”)of the polyester resin is 0° C. to 130° C., and more preferably is 10°C. to 85° C. If the Tg is lower than 0° C., for example, a blockingphenomenon may occurs, in which laminated layers are mutually adhered.If the Tg exceeds 130° C., it is undesirable, because the stability andthe dispersibility in water of the resin may become poor.

The above-described polyester resins and other resins may be used alone,or two different types of resin, for example, a polyester resin and anurethane resin, a polyester resin and an acrylic resin, or an urethaneresin and an acrylic resin, may be used in combination. As a matter ofcourse, at least three types may be used in combination. Preferably, amixture of resins is used because in many cases, characteristics ofrespective resins are exhibited.

In the case that, for example, printing ink is provided on the laminatedfilm, the laminated layer of the laminated film may contain resins otherthan the above-described resins within the range of not impairing thedesired effects.

For example, antioxidants, heat stabilizers, weathering stabilizers,ultraviolet absorbers, organic lubricants, pigments, dyes, organic orinorganic fine particles, fillers, antistatic agents, nucleating agents,and the like may also be compounded within the range of not impairingthe effects.

There are various methods for providing a laminated layer on athermoplastic resin film. In the case that the laminated film isprepared, a so-called in-line coating method may be suitable for use, inwhich application of a coating solution, drying, stretching, and a heattreatment are performed in a film formation step.

The adoption of the in-line coating method provides merits, for example,that the thickness of the laminated layer can be reduced and that theadhesion to a base film is increased, when compared with off-lineprocessing. In particular, since the cross-linking agent (B) is used asan indispensable component, a heat treatment is required for thereaction of the cross-linking agent (B) and, therefore, the in-linecoating method capable of performing a high-temperature heat treatmenthas a significant advantage. That is, in the in-line coating methodcapable of performing a high-temperature heat treatment, since both endsof a film are grasped with clips during the heat treatment, there is amerit that no wrinkle occurs in the laminated film and the flatness ismaintained. On the other hand, in the off-line processing, wrinkles mayoccur in the film due to thermal shrinkage and the flatness of the filmafter processing may be significantly deteriorated. Preferably, the heattreatment in the in-line coating method is performed at 200° C. or more.

The thermoplastic resin film collectively refers to films which aremelted or softened due to heat, and are not specifically limited.Typical examples of thermoplastic resin films may include polyesterfilms; polyolefin films, e.g., polypropylene films and polyethylenefilms; polylactic acid films; polycarbonate films; acrylic films, e.g.,polymethylmethacrylate films and polystyrene films; polyamide films,e.g., nylon; polyvinyl chloride films; polyurethane films;fluorine-based films; and polyphenylene sulfide films.

The thermoplastic resin films may be homopolymers or copolymers. Amongthem, polyester films, polypropylene films, polyamide films, and thelike are preferable from the viewpoint of mechanical properties, thedimensional stability, the transparency, and the like. Furthermore,polyester films are particularly preferable from the viewpoint ofmechanical properties, the general versatility, and the like.

The laminated film will be described below with reference to thepolyester film as a typical example, although not limited to this.

With respect to the polyester film of the laminated film, polyestercollectively refers to polymers in which ester bonding is a primarybonding chain in a main chain. Preferable polyesters include at leastone constituent selected from the group consisting of ethyleneterephthalate, propylene terephthalate, ethylene-2,6-naphthalate,butylene terephthalate, propylene-2,6-naphthalate, ethylene-α,β-bis(2-chlorophenoxy)ethane-4,4′-dicarboxylate, and the like as aprimary constituent. These constituents may be used alone or incombination. Most of all, it is particularly preferable to use apolyester including ethylene terephthalate as a primary constituent,that is, polyethylene terephthalate, considering all the factors, e.g.,quality and economy, involved. When the polyester is used for thepurpose in which heat, shrinkage stress, and the like are applied to abase material, polyethylene-2,6-naphthalate having excellent heatresistant and stiffness is further preferable.

Other dicarboxylic acid components and diol components may becopolymerized as a part of these polyesters, preferably at 20 molepercent or less.

This polyester may contain various additives, e.g., antioxidants, heatstabilizers, weathering stabilizers, ultraviolet absorbers, organiclubricants, pigments, dyes, organic or inorganic fine particles,fillers, antistatic agents, and nucleating agents, to the extent thatthe characteristics are not deteriorated.

Preferably, inorganic particles, e.g., silica, colloidal silica,alumina, alumina sol, kaolin, talc, mica, calcium carbonate, bariumsulfate, carbon black, zeolite, titanium oxide, and a fine metal powder,are added to the polyester film because the slidability is improved.Preferably, the average particle diameter of the inorganic particles is0.005 to 3 μm, and more preferably is 0.05 to 1 μm. Preferably, theamount of addition of the inorganic particles is 0.001 to 5 percent byweight, and more preferably is 0.1 to 2 percent by weight.

The laminated film may be a composite film composed of at least twolayers including an inner layer and a surface layer. The laminated filmmay be, for example, a composite film in which an inner layer portioncontains substantially no particle, and a layer containing particles isprovided in the surface layer portion, or a composite film in which aninner layer portion contains coarse particles and a surface layerportion contains fine particles. In the above-described composite film,the inner layer portion and the surface layer portion may be composed ofdifferent polymers or be composed of the same type of polymer.

Preferably, the intrinsic viscosity (measured in o-chlorophenol at 25°C.) of the above-described polyester is within the range of 0.4 to 1.2dl/g, and more preferably is 0.5 to 0.8 dl/g.

In the state in which a laminated layer is provided, preferably, thepolyester film including the above-described polyester has beenbiaxially oriented. In general, the biaxially oriented polyester filmrefers to a polyester film which is prepared by stretching a polyestersheet or film in a non-stretched state in a longitudinal direction and awidth direction by about 2.5 to 5 times each and, thereafter, performinga heat treatment to complete crystalline orientation and which exhibitsa wide-angle X-ray diffraction pattern attributed to biaxialorientation.

Preferably, the thickness of the laminated layer is usually 0.005 to 5μm, more preferably is 0.01 to 1 μm, and most preferably is 0.03 μm to0.5 μm. If the thickness of the laminated layer is too small, theantistatic property may become poor.

The thickness of the polyester film is not specifically limited, and isappropriately selected in accordance with the use of the laminated film.Preferably, the thickness is usually 1 to 500 μm, more preferably is 5to 300 μm, and most preferably is 9 to 210 μm from the viewpoint of themechanical strength, handleability, and the like. Furthermore, theresulting films may be used after being bonded together by variousmethods.

A laminated layer refers to a film-shaped layer provided to constitute alaminated structure and, thereby, presents on a surface of athermoplastic resin film for serving as a base material. The layeritself may be a single layer or be composed of a plurality of layers.

A method for manufacturing a laminated film includes the steps ofapplying a coating solution containing a composition (A) and across-linking agent (B) to at least one surface of a thermoplastic resinfilm, and performing drying, stretching and, thereafter, heat-treating,wherein the composition (A) is a composition comprising a polythiopheneand a polyanion or a composition comprising a polythiophene derivativeand a polyanion, and 10 to 85 percent by weight of cross-linking agent(B) is contained in the coating solution.

In the method for manufacturing a laminated film, an in-line coatingmethod is preferable as the coating method.

In the in-line coating method, for example, a melt-extruded polyesterfilm before crystalline orientation is effected is stretched by 2.5 to 5times in a longitudinal direction, and the resulting monoaxiallyoriented film is continuously coated with a coating solution. The coatedfilm is dried while being passed through a stepwise-heated zone, and isstretched by 2.5 to 5 times in a width direction. Furthermore, theresulting film is continuously led to a heating zone at 150° C. to 250°C., and crystalline orientation is completed. In a general method, afilm is stretched in a longitudinal direction, and after coating isperformed, the film is stretched in a width direction. However, variousmethods may be used, and examples thereof include a method in which afilm is stretched in a width direction, and after coating is performed,the film is stretched in a longitudinal direction and a method in whichcoating is performed and, thereafter, a film is stretched simultaneouslyin a longitudinal direction and in a width direction.

Before the coating solution is applied, preferably, a surface of a basefilm (the monoaxially oriented film in the above-described case) issubjected to a corona discharge treatment and the like in order that thewetting tension of the base film surface becomes preferably at least 47mN/m, and more preferably at least 50 mN/m because the adhesion to thebase film and the coating property of the laminated layer can beimproved. It is also preferable that small amounts of organic solvent,e.g., isopropyl alcohol, butyl cellosolve, or N-methyl-2-pyrrolidone, iscontained in the coating solution and, thereby, the wettability and theadhesion to the base film is improved.

Various coating method may be used as the method for coating the basefilm. Examples of coating methods may include a reverse coating method,a gravure coating method, a rod coating method, a bar coating method, aMeyer bar coating method, a die coating method, and a spray coatingmethod.

In the method for manufacturing a laminated film, preferably, thecross-linking agent (B) is a water-soluble cross-linking agent.

The method for manufacturing a laminated film will be described below infurther detail with reference to the example in which polyethyleneterephthalate (hereafter abbreviated as “PET”) is used as the base film,although not limited to this.

The method for manufacturing a laminated film will be described withreference to further specific example.

PET pellets having a intrinsic viscosity of 0.5 to 0.8 dl/g arevacuum-dried and, thereafter, are supplied to an extruder. The pelletsare melted at 260° C. to 300° C., and are extruded from a T-die into theshape of a sheet. The resulting sheet is wound around a mirror-finishedcasting drum having a surface temperature of 10° C. to 60° C. by the useof an electrostatic casting method, followed by cooling and solidifying,so that a non-stretched PET film is prepared. This non-stretched film isstretched by 2.5 to 5 times in a longitudinal direction (film travelingdirection) between rolls heated to 70° C. to 120° C. At least onesurface of this film is subjected to a corona discharge treatment inorder that the wetting tension of the surface becomes at least 47 mN/m,and the treated surface is coated with the water-based coating solution.This coated film is grasped with clips, and is led to a hot-air zoneheated to 70° C. to 150° C. After drying is performed, the film isstretched by 2.5 to 5 times in a width direction, and subsequently, isled to a heat treatment zone at 160° C. to 250° C. A heat treatment isperformed for 1 to 30 seconds, so that crystalline orientation iscompleted. If necessary, a treatment for relaxation of 1 to 10 percentin a width direction or a longitudinal direction may be performed duringthis heat treatment step. Biaxial stretching may be performedsuccessively in a longitudinal direction and in a width direction, orsimultaneous biaxial stretching may be performed. After stretching isperformed in a longitudinal direction and in a width direction,re-stretching may be performed in any one of the longitudinal directionand the width direction. The thickness of the polyester film is notspecifically limited, but preferably, the thickness is 1 to 500 μm.

When the base film to be provided with the laminated layer is allowed tocontain at least one material selected from a laminated layer-formingcomposition or reaction products of the laminated layer-formingcomposition, the adhesion between the laminated layer and the base filmcan be improved, and the slidability of the laminated polyester film canbe improved. With respect to the amount of addition of the laminatedlayer-forming composition or reaction products thereof, preferably, atotal of the amounts of addition is 5 ppm or more and less than 20percent by weight from the viewpoint of the adhesion and theslidability. In consideration of environmental protection andproductivity, a method in which recycled pellets containing thelaminated layer-forming composition are used is suitable.

The laminated film is particularly suitable for use as a laminated filmfor a protective film. An adhesive layer may be provided on at least onesurface of the laminated film, so that a protective film may beprovided.

The laminated film is particularly suitable for use as a laminated filmfor a cover tape. A layer composed of a polyolefin-based resin and/or anadhesive layer having a thickness of 0.5 to 20 μm may be provided on atleast one surface of the laminated film, so that a cover tape havingexcellent characteristics may be provided.

The laminated film is particularly suitable for use as a laminated filmfor a carrier package. A carrier tape may be laminated on at least onesurface of the laminated film, so that a carrier package may beprovided.

A laminated film for a protective film is manufactured by a methodincluding the steps of applying a coating solution containing acomposition (A) and a cross-linking agent (B) to at least one surface ofa thermoplastic resin film, and performing drying, stretching and,thereafter, heat-treating, wherein the composition (A) is a compositioncomprising a polythiophene and a polyanion or a composition comprising apolythiophene derivative and a polyanion, and 25 to 85 percent by weightof cross-linking agent (B) is contained in the coating solution.

In the laminated film for a protective film, preferably, thecross-linking agent (B) is a water-soluble cross-linking agent.

With respect to the laminated film for a protective film, preferably,the haze is 2 percent or less. In particular, when the film is used forcomponents related to liquid crystal displays, if the haze exceeds 2percent, problems occur in that the light transmission is reduced, theluminance is reduced, the image becomes blurred, and the like. Morepreferably, the haze is 1.5 percent or less, and most preferably is 1percent or less.

With respect to the laminated film for a protective film, preferably,the thermal shrinkage is −0.5 percent or more and 1 percent or less. Inparticular, when the film is used for components related to liquidcrystal displays, since the film may be affixed to a display screen by aheat treatment, e.g., autoclaving, or a heat treatment may be performedto provide an adhesive layer, it is important that occurrence of thermalshrinkage of the protective film itself is minimized. The protectivefilm in the state of being affixed may become commercial or may be usedwithout being processed. At this time, the thermal shrinkage is animportant characteristic because of, for example, heat generation by adisplay itself and harsh use environments, e.g., a high temperaturecondition during car navigation use in the interior of a car. When thethermal shrinkage is −0.5 percent or more and 1 percent or less, nodistortion occurs during inspection, and no distortion occurs in animage. A smaller thermal shrinkage is preferable, and a thermalshrinkage of 0 percent to 0.5 percent is more preferable. A negativethermal shrinkage indicates that the film expands, as described in theitem of evaluation.

An adhesive layer is provided on at least one surface of the laminatedfilm for a protective film and, thereby, a protective film havingexcellent characteristics is provided.

That is, the protective film may be produced by providing the adhesivelayer on the above-described laminated film for a protective film.

The type of the adhesive layer is not specifically limited as long asthe layer has adhesion property, and rubber-based adhesives, acrylicadhesives, vinyl-based adhesives, polyester-based adhesives,silicone-based, and the like may be used. For example, the rubber-basedadhesive to be used may primarily contain a rubber elastomer, asoftener, and a tackifier, and if necessary, a filler and an antioxidantmay be added. The acrylic adhesive to be used may primarily contain anacrylate, e.g., butyl acrylate, 2-ethylhexyl acrylate, or the like, andin order to adjust a cohesive force, vinyl acetate, ethylene-acrylicacid, or the like may be copolymerized. The silicone-based adhesive tobe used may primarily contain a mixture of rubber-like siloxane and apolymer of resin-like siloxane.

The method for providing the adhesive layer is not specifically limited.However, methods through the use of coating are suitable, and a diecoating method, a doctor blade method, a gravure coating method, and thelike may be used. The thickness of the adhesive layer is notspecifically limited. However, adhesive layers having thicknesses withinthe range of 0.5 to 20 μm are suitable for use.

Preferably, the adhesive layer is imparted with an antistatic property,and antistatic agents, e.g., carbon black, tin oxide, antimony-doped tinoxide, polythiophene, and polyaniline, may be used. Tin oxide-basedantistatic agents are suitable in consideration of the transparency.

When the protective film is manufactured, an adhesive layer is providedon the protective film. An adhesive constituting this adhesive layer maylie off the edge so as to adhere to the protective film surface.Furthermore, lubricating oil and the like in the process may also adhereto the surface. In an inspection step to determine whether adherents,e.g., an adhesive and lubricating oil, makes defects of a liquid crystalpolarizer itself or not, when the protective film is affixed to thepolarizer or the like the workability may be deteriorated and defectsmay be missed. In order to prevent this, in most instances, for example,small amounts of alcohol, e.g., ethanol, or general-purpose organicsolvent, e.g., methyl ethyl ketone or toluene, is used, and the surfaceside of the liquid crystal polarizer is lightly wiped clean. At thistime, if the laminated layer used for the protective film has no solventresistance, the laminated layer surface is attacked by theabove-described organic solvent, and problems occur in that, forexample, the laminated layer is whitened and fallen off and, thereby,the inspection with the polarizer becomes impossible.

A cross-linking agent, most of all, an epoxy-based cross-linking agent,is used preferably as an indispensable component of the laminated layerand, thereby, the cross-linking property is very high. In addition,since polyanions serving as dopants of polythiophene, for example,polystyrenesulfonic acid, are present, cross-linking reaction advancesvery speedily at a temperature of the heat treatment performed after thein-line coating, very high degree of cross-linking structure is formedand, thereby, the solvent resistance of the laminated layer isexhibited.

A laminated film for a cover tape is manufactured by a method includingthe steps of applying a coating solution containing a composition (A)and a cross-linking agent (B) to at least one surface of a thermoplasticresin film, and performing drying, stretching and, thereafter,heat-treating, wherein the composition (A) is a composition comprising apolythiophene and a polyanion or a composition comprising apolythiophene derivative and a polyanion, and 10 to 85 percent by weightof cross-linking agent (B) is contained in the coating solution. In thelaminated film for a cover tape, preferably, the cross-linking agent (B)is a water-soluble cross-linking agent.

A polyolefin resin layer and/or an adhesive layer is provided on atleast one surface of the laminated film for a cover tape and, thereby, acover tape having excellent characteristics may be provided.

With respect to the cover tape, resins having a heat sealing property,e.g., polyethylenes, polypropylenes, ethylene propylene copolymers,polystyrenes, and cyclohexanedimethanol copolymerization polyesters, maybe suitable for use as the polyolefin-based resin. Among them,polyethylenes are most preferable from the viewpoint of generalversatility and moldability.

The adhesive layer used for the cover tape is not specifically limitedas long as the layer has adhesion properties, and rubber-basedadhesives, acrylic adhesives, vinyl-based adhesives, polyester-basedadhesives, silicone-based, and the like may be used. For example, therubber-based adhesive to be used may primarily contain a rubberelastomer, a softener, and a tackifier, and if necessary, a filler andan antioxidant may be added. The acrylic adhesive to be used mayprimarily contain an acrylate, e.g., butyl acrylate, 2-ethylhexylacrylate, or the like, and in order to adjust a cohesive force, vinylacetate, ethylene-acrylic acid, or the like may be copolymerized. Thesilicone-based adhesive to be used may primarily contain a mixture ofrubber-like siloxane and a polymer of resin-like siloxane.

In the cover tape, the method for providing the polyolefin-based resinlayer and/or the adhesive layer is not specifically limited. Forexample, methods through the use of coating, a lamination method, a heatsealing method, and a coextrusion method may be used, and the laminationmethod is most suitable, in which a polyethylene resin sheet or film islaminated through the use of heat or the like. The thickness of thepolyolefin-based resin layer and/or an adhesive layer is usually 0.5 to20 μm, preferably is 2 to 15 μm, more preferably is 5 to 12 μm. If thepolyolefin-based resin layer and/or the adhesive layer is too thin, theheat sealing effect cannot be exhibited, and, in addition, the handlingduring lamination becomes difficult. On the other hand, if the thicknessis too large, a carrier package taken up into the shape of a reelbecomes too large and, in addition, since the heat transfer during heatsealing becomes inadequate, variations may occur in heat sealing forceand unexpected troubles may occur.

In the cover tape, preferably, the contact angle of water on the surfaceof the polyolefin-based resin layer and/or an adhesive layer is 80 to110 degrees, and more preferably is 85 to 105 degrees. Here, the surfaceof the polyolefin-based resin layer and/or the adhesive layer refers tothe surface in the side laminated on the carrier tape, while the contactangle of water on the surface is measured. The cover tape in the stateof being laminated on the carrier tape by heat lamination or the like soas to constitute the carrier package is peeled off the carrier tape and,thereafter, the contact angle of water on the surface is measured.

When the contact angle of water on the surface of the polyolefin-basedresin layer and/or the adhesive layer is 80 to 110 degrees, the affinitywith the resin constituting the carrier tape is adequate, and the heatsealing force as the cover tape does not become short. On the otherhand, no detrimental effect, e.g., the difficulty in peeling or thesusceptibility to peeling electrification, due to excessively high heatsealing property relative to the carrier tape is exhibited.

Preferably, the polyolefin-based resin layer and/or the adhesive layeris also imparted with an antistatic property, and antistatic agents,e.g., carbon black, tin oxide, antimony-doped tin oxide, polythiophene,and polyaniline, may be used. Tin oxide-based antistatic agents aresuitable in consideration of the transparency.

A polyolefin-based resin layer and/or an adhesive layer of 0.5 to 20 μmin thickness is provided on at least one surface of the laminated filmfor a cover tape, and a carrier tape is laminated on thepolyolefin-based resin layer and/or the adhesive layer, so that acarrier package may be provided.

The method for laminating the carrier tape on the polyolefin-based resinlayer and/or the adhesive layer is not specifically limited, and amethod, for example, a heat sealing method and a lamination method,similar to that used in the above-described manufacture of the covertape may be used. At this time, recessed portions to store electroniccomponents and the like may be provided in the carrier tape and the likein advance.

With respect to the above-described recessed portions to storeelectronic components, the recessed portions adjusted to the shape ofthe electronic components to be inserted, for example, IC chips andcapacitors, are formed by molding with a molding machine, so that acarrier tape may be provided. The above-described cover tape and thecarrier tape in the state of including electronic components may belaminated by heat sealing or the like, so that a carrier package may beprovided.

Since the recessed portions to store electronic components and the likeare provided in the carrier tape and the like in advance, when thelaminated film for a cover tape is used for the cover tape and thecarrier package, peeling electrification during peeling from the carriertape is suppressed at an extremely high suppression level. Consequently,excellent characteristics can be exhibited, for example, electroniccomponents, e.g., IC circuits, in the carrier tape are not released, andno discharge occurs due to accumulation of electrification charge.

Methods for measuring characteristics and methods for evaluating desiredeffects are as described below.

(1) Thickness of Laminated Layer

A transmission electron microscope Model HU-12 produced by Hitachi,Ltd., was used. The thickness was determined from a photograph based onthe observation of a cross section of a laminated polyester filmprovided with a laminated layer. An average value of 30 measurements ina measurement field of view was taken as the thickness.

(2) Transparency

The transparency was measured based on the haze. A laminated film wasstood for 2 hours at normal conditions (23° C., relative humidity 65percent) and, thereafter, the haze was measured with a fully automaticdirect-reading Haze Computer “HGM-2DP” produced by SUGA TEST INSTRUMENTSCo., Ltd. An average value of 3 measurements was taken as the haze valueof the sample.

(3) Antistatic Property

The antistatic property was measured based on the surface resistivity. Asample was stood for 24 hours at normal conditions (23° C., relativehumidity 65 percent) and, in that atmosphere, after application of anapplied voltage of 100 V for 10 seconds, the surface resistivity wasmeasured with a digital super-high resistance/microammeter R8340A(produced by ADVANTEST CORPORATION). The unit is Ω/□. When the level ofthe surface resistivity is 1×10¹² Ω/□ or less, no problem occurs inpractice. When the surface resistivity is 1×10¹⁰ Ω/□ or less, inparticular is 1×10⁹ Ω/□ or less, excellent antistatic property isexhibited.

In addition, an evaluation similar to that described above was alsoperformed at a relative humidity of 25 percent, so that an evaluation tocheck the humidity dependence was performed.

(4) Water Resistance

After a laminated film was exposed to running tap water for 1 minute,air drying was performed at 40° C. for 10 minutes. Subsequently, theantistatic property was evaluated as described in the item (3). Thelaminated film which exhibits small difference between the antistaticproperty before subjected to the water resistance evaluation and theantistatic property after subjected to the water resistance evaluationis a laminated film having excellent water resistance.

(5) Scratch Resistance

A laminated layer provided on a thermoplastic resin film was scratchedwith a nail, and the degree of the damage was visually evaluated asdescribed below. Symbols (⊙) and (◯) indicate good scratch resistance.

(⊙): no damage

(◯): a scratch mark is left on the laminated layer

(Δ): the laminated layer is gouged by scratching with a nail

(x): the laminated layer is scraped and powder-like shavings are formed

(6) Observation of Cross Section of Laminated Layer

An extremely thin slice was cut out perpendicularly to a film surface ofa laminated film, and the resulting laminated film was stained by osmicacid (OSO₄). The laminated layer portion in the extremely thin slicestained by osmic acid was observed with a transmission electronmicroscope (H-7100FA, produced by Hitachi, Ltd.) at an accelerationvoltage of 100 kV.

It was checked by the following method whether each of components usedfor the laminated layer had stainability with osmic acid or had nostainability with osmic acid.

Comparative Sample (1):

a sample prepared by applying a complex composed ofpolyethylenedioxythiophene/polystyrenesulfonic acid to a PET film,followed by drying

Comparative Sample (2):

a sample prepared by applying an epoxy cross-linking agent to a PETfilm, followed by drying

Here, two samples were further prepared with respect to Comparativesample (1).

Comparative Sample (1)-1:

a sample subjected to TEM cross-sectional observation without beingstained by osmic acid

Comparative Sample (1)-2:

a sample subjected to TEM cross-sectional observation after beingstained by osmic acid

When TEM cross-sectional observation images of Comparative sample (1)-1and Comparative sample (1)-2 were compared, no difference inconcentration was recognized between the two. Consequently, it wasascertained that the compound used in Comparative sample (1), which wasthe complex composed of polyethylenedioxythiophene/polystyrenesulfonicacid, was not stained by osmic acid.

When a TEM cross-sectional observation image of Comparative sample (2)was compared with that of Comparative sample (1), Comparative sample (2)was stained clearly at a high concentration. Consequently, it wasascertained that the epoxy cross-linking agent, which was a compoundused in Comparative sample (2), was stained by osmic acid.

(7) Solvent Resistance

With respect to the laminated layer of the laminated film or thelaminated layer of the protective film, the solvent resistance wasevaluated based on the following criteria, wherein three types ofgeneral-purpose organic solvent including ethanol (represented bysolvent “1” in the Table), methyl ethyl ketone (represented by solvent“2” in the Table), and toluene (represented by solvent “3” in the Table)were used.

An end of a cotton swab was impregnated with each of the above-describedorganic solvents, the angle of the cotton swab was maintained at 45degrees, and the cotton swab was allowed to reciprocate 10 times under aload of iN at a speed of 6 cm/sec over distances of 3 cm on thelaminated layer. Thereafter, the state of the laminated layer wasvisually observed. The laminated layer rated as 4 or 5 has good solventresistance.

rating 5: no change is observed

rating 4: scuffs are observed to some extent, but the laminated layerremains

rating 3: the laminated layer is partially taken off

rating 2: a thin line shaped portion is taken off the laminated layer.

rating 1: all portions rubbed with the cotton swab are taken off thelaminated layer.

(8) Thermal Shrinkage

The measurement was performed in accordance with JIS C 2318, asdescribed below.

With respect to a laminated film, in particular, a laminated film for aprotective film, the laminated film was cut into the size of about 200mm×about 10 mm, the resulting sample was stood for 8 hours in anatmosphere at 23° C. and a relative humidity of 65 percent and,thereafter, two points spaced about 150 mm in a longitudinal directionwere marked on the sample. The spacing between the marks was measuredwith a linear scale length measuring machine, and the value wasindicated by A₀. Likewise, two points spaced about 70 mm in a directionorthogonal to the longitudinal direction were marked on the sample, andthe value thereof was indicated by B₀. The sample was stood for 30minutes in an atmosphere at 150° C. and, thereafter, was stood again for8 hours at 23° C. and a relative humidity of 65 percent. In thatatmosphere, the spacing between the above-described two marks wasmeasured, and the values in the longitudinal direction and in thedirection orthogonal thereto were indicated by A and B, respectively. Atthis time, the thermal shrinkage was determined as an average thereofbased on the following equation.thermal shrinkage (percent)=100×((A ₀ −A)/A ₀+(B ₀ −B)/B ₀)

(9) Scratch Resistance-2

The laminated film, in particular, the laminated film for a cover tapeis used for the purpose of including electronic components. Therefore,shavings, a residue, and the like of the laminated layer cause extremelysignificant troubles. Consequently, the scratch resistance of thelaminated layer is an important characteristic.

A model for the scratching during processing step was formulated, and asample of 25 mm in width and 50 cm in length was prepared. A cylindricalstainless steel bar of 6 mm in diameter was loaded with 5 N, and wasallowed to reciprocate 20 times on the laminated layer surface of thelaminated film. Subsequently, the state of the laminated layer powderand the like adhered to the bar and the state of the coating film wasobserved, so that the scratch resistance was evaluated. The criteria ofevaluation are as described below, and the rating of at least 4indicates good scratch resistance.

rating 5: no powder is adhered to the bar, nor is damage observed on thelaminated layer

rating 4: no powder is adhered to the bar, but damage is observedslightly on the laminated layer

rating 3: a powder is adhered to the bar, and damage is observed on thelaminated layer

rating 2: large amounts of powder is adhered to the bar, and damage isobserved on the laminated layer

rating 1: large amounts of powder is adhered to the bar, and thelaminated layer has almost fallen off

(10) Measurement of Contact Angle

A sample was stood for 24 hours at normal conditions (23° C., relativehumidity 65 percent) and, in that atmosphere, the contact angle wasmeasured with a contact angle meter Model CA-D (produced by KYOWAINTERFACE SCIENCE CO., LTD.) through the use of distilled water whichhad been stored under similar conditions. An average value of 10 sampleswere taken as the measurement value.

(11) Static Voltage

A sample was stood for 24 hours at normal conditions (23° C., relativehumidity 65 percent). In that atmosphere, an honestmeter (“STATICHONESTMETER” TYPE S-5109 produced by SHISHIDO ELECTROSTATIC, LTD.) wasused, and after application of an applied voltage of 10 V for 12 secondsat an irradiation height of 2 cm, with respect to the electric chargeattenuation behavior of the sample at a detection height of 2 cm, theelapsed time (sec) after the application and the static voltage (V) ofthe sample were plotted by the use of a recorder. The number ofrevolutions of a turn table was 1,550 rpm.

EXAMPLES

The films will be described below with reference to examples. However,the films are not limited to them.

Example 1

PET pellets (intrinsic viscosity 0.63 dl/g) containing 0.015 percent byweight of colloidal silica having an average particle diameter of 0.4 μmand 0.005 percent by weight of colloidal silica having an averageparticle diameter of 1.5 μm were adequately vacuum-dried and,thereafter, were supplied to an extruder. The pellets were melted at285° C., and were extruded from a T-die into the shape of a sheet. Theresulting sheet was wound around a mirror-finished casting drum having asurface temperature of 25° C. by the use of an electrostatic castingmethod, followed by cooling and solidifying. The resulting non-stretchedfilm was heated to 92° C., and was stretched by 3.3 times in alongitudinal direction, so that a monoaxially stretched film wasprepared. This film was subjected to a corona discharge treatment in airin order that the wetting tension of the base film became 55 mN/m, andthe treated surface was coated with a laminated layer-forming coatingsolution described below. The coated monoaxially stretched film wasgrasped with clips, and was led to a preheating zone. After drying wasperformed at 90° C., the film was continuously stretched by 3.8 times ina width direction in a heating zone at 90° C., and furthermore, wassubjected to a heat treatment in a heating zone at 225° C., so that alaminated PET film was prepared, wherein crystalline orientation wascompleted. At this time, the thickness of the base PET film was 38 μm,and the thickness of the laminated layer was 0.02 μm. The results areshown in Table 1. Excellent transparency, antistatic property, and waterresistance were exhibited. A TEM cross-section observation image of thelaminated layer of the present Example is shown in FIG. 2. A “sea”portion made of a complex composed ofpolyethylenedioxythiophene/polystyrenesulfonic acid and “island”portions composed of an epoxy cross-linking agent were observed, so thatthe laminated layer had a sea-island structure.

“Laminated Layer-Forming Coating Solution”

Coating Solution A1:

a water-based coating solution (“DENATRON” #5002SZ produced by NagaseChemteX Corporation) in which a fluorine-based surfactant was added to acomplex composed of polyethylenedioxythiophene/polystyrenesulfonic acid.

Coating Solution B1:

a water-based coating solution in which polyglycerol polyglycidylether-based epoxy cross-linking agent (“DENACOL” EX-512 produced byNagase ChemteX Corporation (molecular weight about 630, weight per epoxyequivalent 168, water solubility 100 percent)) serving as an epoxycross-linking agent was dissolved in water.

A laminated layer-forming coating solution was prepared by mixing theabove-described Coating solution A1 and Coating solution B1 at a ratioof Coating solution A1/Coating solution B1=10/90 on a weight of solidbasis.

Example 2

PET pellets (intrinsic viscosity 0.63 dl/g) containing 0.015 percent byweight of colloidal silica having an average particle diameter of 0.4 μmand 0.005 percent by weight of colloidal silica having an averageparticle diameter of 1.5 μm were adequately vacuum-dried and,thereafter, were supplied to an extruder. The pellets were melted at285° C., and were extruded from a T-die into the shape of a sheet. Theresulting sheet was wound around a mirror-finished casting drum having asurface temperature of 25° C. by the use of an electrostatic castingmethod, followed by cooling and solidifying. The resulting non-stretchedfilm was heated to 92° C., and was stretched by 3.3 times in alongitudinal direction, so that a monoaxially stretched film wasprepared. This film was subjected to a corona discharge treatment in airin order that the wetting tension of the base film became 55 mN/m, andthe treated surface was coated with a laminated layer-forming coatingsolution described below. The coated monoaxially stretched film wasgrasped with clips, and was led to a preheating zone. After drying wasperformed at 90° C., the film was continuously stretched by 3.8 times ina width direction in a heating zone at 90° C., and furthermore, wassubjected to a heat treatment in a heating zone at 225° C., so that alaminated PET film was prepared, wherein crystalline orientation wascompleted. At this time, the thickness of the base PET film was 38 μm,and the thickness of the laminated layer was 0.05 μm. The results areshown in Table 1. Excellent transparency, antistatic property, and waterresistance were exhibited.

“Laminated Layer-Forming Coating Solution”

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution B2:

a water-based coating solution in which sorbitol polyglycidylether-based epoxy cross-linking agent (“DENACOL” EX-614B produced byNagase ChemteX Corporation (molecular weight about 550, weight per epoxyequivalent 173, water solubility 94 percent)) serving as an epoxycross-linking agent was dissolved in water.

A laminated layer-forming coating solution was prepared by mixing theabove-described Coating solution A2 and Coating solution B2 at a ratioof Coating solution A2/Coating solution B2=20/80 on a weight of solidbasis.

Example 3

A laminated film was prepared as in Example 2 except that Coatingsolution A2 and Coating solution B3 were used in the laminatedlayer-forming coating solution in Example 2. The results are shown inTable 1. Excellent transparency, antistatic property, and waterresistance were exhibited.

“Laminated Layer-Forming Coating Solution”

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution B3:

a water-based coating solution in which polyglycerol polyglycidylether-based epoxy cross-linking agent (“DENACOL” EX-521 produced byNagase ChemteX Corporation (molecular weight about 1,000, weight perepoxy equivalent 183, water solubility 100 percent)) serving as an epoxycross-linking agent was dissolved in water.

A laminated layer-forming coating solution was prepared by mixing theabove-described Coating solution A2 and Coating solution B3 at a ratioof Coating solution A2/Coating solution B3=20/80 on a weight of solidbasis.

Example 4

A laminated film was prepared as in Example 2 except that Coatingsolution A2 and Coating solution B1 were used in the laminatedlayer-forming coating solution in Example 2. The results are shown inTable 1. Excellent transparency, antistatic property, and waterresistance were exhibited and, in addition, extremely excellent scratchresistance was exhibited.

“Laminated Layer-Forming Coating Solution”

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution B1:

a water-based coating solution in which polyglycerol polyglycidylether-based epoxy cross-linking agent (“DENACOL” EX-512 produced byNagase ChemteX Corporation (molecular weight about 630, weight per epoxyequivalent 168, water solubility 100 percent)) serving as an epoxycross-linking agent was dissolved in water.

A laminated layer-forming coating solution was prepared by mixing theabove-described Coating solution A2 and Coating solution B1 at a ratioof Coating solution A2/Coating solution B1=15/85 on a weight of solidbasis.

Example 5

A laminated film was prepared as in Example 2 except that Coatingsolution A2 and Coating solution B1 were used in the laminatedlayer-forming coating solution in Example 2, while Coating solution A2and Coating solution B1 were used after mixing at a ratio of 20/80(weight ratio of solid). The results are shown in Table 1. Excellenttransparency, antistatic property, and water resistance were exhibited.

Example 6

A laminated film was prepared as in Example 2 except that Coatingsolution A2 and Coating solution B1 were used in the laminatedlayer-forming coating solution in Example 2, while Coating solution A2and Coating solution B1 were used after mixing at a ratio of 30/70(weight ratio of solid). The results are shown in Table 1. Excellenttransparency, antistatic property, and water resistance were exhibited.

Example 7

A laminated film was prepared as in Example 2 except that Coatingsolution A2 and Coating solution B1 were used in the laminatedlayer-forming coating solution in Example 2, while Coating solution A2and Coating solution B1 were used after mixing at a ratio of 50/50(weight ratio of solid). The results are shown in Table 1. Excellenttransparency, antistatic property, and water resistance were exhibited.

Example 8

A laminated film was prepared as in Example 2 except that Coatingsolution A2 and Coating solution B1 were used in the laminatedlayer-forming coating solution in Example 2, while Coating solution A2and Coating solution B1 were used after mixing at a ratio of 75/25(weight ratio of solid). The results are shown in Table 1. Excellenttransparency, antistatic property, and water resistance were exhibited.

Example 9

A laminated film was prepared as in Example 2 except that Coatingsolution A2 and Coating solution B1 were used in the laminatedlayer-forming coating solution in Example 2, while Coating solution A2and Coating solution B1 were used after mixing at a ratio of 90/10(weight ratio of solid). The results are shown in Table 1. Excellenttransparency, antistatic property, and water resistance were exhibited.

Example 10

A laminated film was prepared as in Example 2 except that Coatingsolution A2 and Coating solution B1 were used in the laminatedlayer-forming coating solution in Example 2, while Coating solution A2and Coating solution B1 were used after mixing at a ratio of 25/75(weight ratio of solid) and the thickness of the laminated layer wascontrolled at 0.025 μm. The results are shown in Table 1. Excellenttransparency, antistatic property, and water resistance were exhibited.

Example 11

A laminated film was prepared as in Example 2 except that Coatingsolution A2 and Coating solution B4 were used in the laminatedlayer-forming coating solution in Example 2 and the thickness of thelaminated layer was controlled at 0.07 μm. The results are shown inTable 1. Excellent transparency, antistatic property, and waterresistance were exhibited and, in addition, excellent scratch resistancewas exhibited as well.

“Laminated Layer-Forming Coating Solution”

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution B4:

a water-based coating solution in which polyglycerol polyglycidylether-based epoxy cross-linking agent (“DENACOL” EX-810 produced byNagase ChemteX Corporation (molecular weight about 180, weight per epoxyequivalent 113, water solubility 100 percent)) serving as an epoxycross-linking agent was dissolved in water.

A laminated layer-forming coating solution was prepared by mixing theabove-described Coating solution A2 and Coating solution B4 at a ratioof Coating solution A2/Coating solution B4=50/50 on a weight of solidbasis.

Example 12

A laminated film was prepared as in Example 2 except that Coatingsolution A2 and Coating solution B5 were used in the laminatedlayer-forming coating solution in Example 2. The results are shown inTable 1. Excellent transparency, antistatic property, and waterresistance were exhibited and, in addition, excellent scratch resistancewas exhibited as well.

“Laminated Layer-Forming Coating Solution”

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution B5:

a water-based coating solution in which methylol type melaminecross-linking agent (“NIKALAC” MW12LF produced by SANWA CHEMICAL CO.,LTD. (molecular weight about 340)) serving as a melamine-basedcross-linking agent was dissolved in water.

A laminated layer-forming coating solution was prepared by mixing theabove-described Coating solution A2 and Coating solution B5 at a ratioof Coating solution A2/Coating solution B5=50/50 on a weight of solidbasis.

Comparative Example 1

A laminated PET film was prepared as in Example 2 except that thefollowing laminated layer-forming coating solution was used in thelaminated layer-forming coating solution in Example 2 and the thicknessof the laminated layer was controlled at 0.07 μm. The results are shownin Table 1. The coating film was whitened and was susceptible toscratching, and in addition, an extremely poor antistatic property wasexhibited.

“Laminated Layer-Forming Coating Solution”

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

The above-described Coating solution A2 was used alone as the laminatedlayer-forming coating solution.

Comparative Example 2

A laminated PET film was prepared as in Comparative example 1 exceptthat the thickness of the laminated layer was controlled at 0.025 μm inComparative example 1. The results are shown in Table 1. The coatingfilm was whitened and was susceptible to scratching, and in addition, anextremely poor antistatic property was exhibited.

Comparative Example 3

A laminated PET film was prepared as in Example 2 except that thefollowing laminated layer-forming coating solution was used as thelaminated layer-forming coating solution in Example 2. The results areshown in Table 1. Since no cross-linking agent (B) was used in thepresent Comparative example, an extremely poor antistatic property wasexhibited.

“Laminated Layer-Forming Coating Solution”

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution C1:

A water-based dispersion (so-called “latex”-like coating solution, watersolubility: 1 percent or less) in which a granular polyester resin(glass transition temperature: 21° C.) composed of the followingcopolymer composition was dispersed in water.

Acid components terephthalic acid 10 mole percent isophthalic acid 78mole percent 5-sodium sulfoisophthalic acid 12 mole percent Diolcomponents ethylene glycol  5 mole percent diethylene glycol 75 molepercent neopentyl glycol 20 mole percent

A laminated layer-forming coating solution was prepared by mixing theabove-described Coating solution A2 and Coating solution C1 at a ratioof Coating solution A2/Coating solution C1=20/80 on a weight of solidbasis.

Comparative Example 4

A laminated PET film was prepared as in Example 2 except that thefollowing laminated layer-forming coating solution was used as thelaminated layer-forming coating solution in Example 2. The results areshown in Table 1. Since no cross-linking agent (B) was used in thepresent Comparative example, the transparency was poor, and theantistatic property was inadequate.

“Laminated Layer-Forming Coating Solution”

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution C2:

a water-based dispersion (so-called “latex”-like coating solution, watersolubility: 1 percent or less) in which a granular acrylic resin (glasstransition temperature: 42° C.) composed of the following copolymercomposition was dispersed in water.

Copolymer components methyl methacrylate 62 mole percent ethyl acrylate35 mole percent acrylic acid  1 mole percent N-methylolacrylamide  2mole percent

A laminated layer-forming coating solution was prepared by mixing theabove-described Coating solution A2 and Coating solution C2 at a ratioof Coating solution A2/Coating solution C2=80/20 on a weight of solidbasis.

Comparative Example 5

A laminated PET film was prepared as in Example 2 except that thefollowing laminated layer-forming coating solution was used as thelaminated layer-forming coating solution in Example 2. The results areshown in Table 1. Since the composition (A) and cross-linking agent (B)were not used in the present Comparative example, the humiditydependence was significant, a poor antistatic property was exhibitedparticularly at a low humidity, and no water resistance was exhibited.

“Laminated Layer-Forming Coating Solution”

Coating Solution D1:

a water-based coating solution in which ammonium polystyrenesulfonate(weight average molecular weight: 65,000) was dissolved in water.

Coating Solution C2:

a water-based dispersion (so-called “latex”-like coating solution, watersolubility: 1 percent or less) in which a granular acrylic resin (glasstransition temperature: 42° C.) composed of the following copolymercomposition was dispersed in water.

Copolymer components methyl methacrylate 62 mole percent ethyl acrylate35 mole percent acrylic acid  1 mole percent N-methylolacrylamide  2mole percent

A laminated layer-forming coating solution was prepared by mixing theabove-described Coating solution D1 and Coating solution C2 at a ratioof Coating solution D1/Coating solution C2=25/75 on a weight of solidbasis.

TABLE 1 Antistatic property Laminated layer Mixing ratio LaminatedRelative Relative composition (Weight ratio layer thickness Hazehumidity humidity Water Scratch Coating solution of solid) (μm) (%) 65%25% resistance resistance Example 1 A1/B1 15/85 0.02 1.2 1 × 10⁸ 1 × 10⁸2 × 10⁸ ◯ Example 2 A2/B2 20/80 0.05 1.2 2 × 10⁸ 2 × 10⁸ 2 × 10⁸ ◯Example 3 A2/B3 20/80 0.05 2.5 4 × 10⁸ 5 × 10⁸ 4 × 10⁸ ◯ Example 4 A2/B115/85 0.05 1.0 2 × 10⁹ 3 × 10⁹ 4 × 10⁹ ⊙ Example 5 A2/B1 20/80 0.05 1.21 × 10⁸ 1 × 10⁸ 1 × 10⁸ ⊙ Example 6 A2/B1 30/70 0.05 1.3 3 × 10⁷ 3 × 10⁷3 × 10⁷ ◯ Example 7 A2/B1 50/50 0.05 1.4 1 × 10⁷ 1 × 10⁷ 1 × 10⁷ ◯Example 8 A2/B1 75/25 0.05 1.9 8 × 10⁶ 8 × 10⁶ 9 × 10⁶ ◯ Example 9 A2/B190/10 0.05 4.8 5 × 10⁷ 5 × 10⁷ 8 × 10⁷ ◯ Example 10 A2/B1 25/75 0.0251.1 3 × 10⁸ 4 × 10⁸ 4 × 10⁸ ◯ Example 11 A2/B4 50/50 0.07 1.3 1 × 10⁷ 1× 10⁷ 1 × 10⁷ ⊙ Example 12 A2/B5 50/50 0.05 4.5 1 × 10¹⁰ 3 × 10¹⁰ 1 ×10¹⁰ ◯ Comparative A2 Application 0.07 24 2 × 10¹⁵ 3 × 10¹⁵ 4 × 10¹⁴ Xexample 1 of A2 alone Comparative A2 Application 0.025 4.7 1 × 10¹⁶ 2 ×10¹⁶ 3 × 10¹⁴ Δ example 2 of A2 alone Comparative A2/C1 20/80 0.05 2.5 4× 10¹⁴ 5 × 10¹⁴ 6 × 10¹³ ⊙ example 3 Comparative A2/C2 80/20 0.05 13 6 ×10¹² 8 × 10¹² 8 × 10¹² ◯ example 4 Comparative D1/C2 25/75 0.05 3.0 2 ×10¹⁰ 5 × 10¹² 4 × 10¹³ X example 5

Example 13

PET pellets (intrinsic viscosity 0.63 dl/g) containing 0.008 percent byweight of aggregated silica having an average particle diameter of 0.7μm and 0.008 percent by weight of aggregated silica having an averageparticle diameter of 1.4 μm were adequately vacuum-dried and,thereafter, were supplied to an extruder. The pellets were melted at285° C., and were extruded from a T-die into the shape of a sheet. Theresulting sheet was wound around a mirror-finished casting drum having asurface temperature of 20° C. by the use of an electrostatic castingmethod, followed by cooling and solidifying. The resulting non-stretchedfilm was heated to 88° C., and was stretched by 3.3 times in alongitudinal direction, so that a monoaxially stretched film wasprepared. This film was subjected to a corona discharge treatment inair, and the treated surface was coated with a laminated layer-formingcoating solution described below.

“Laminated Layer-Forming Coating Solution”

A laminated layer-forming coating solution was prepared by mixing thefollowing Coating solution A2 and Coating solution B6 at a ratio ofCoating solution A2/Coating solution B6=75/25 on a weight of solidbasis.

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution B6:

a water-based coating solution in which a polyethylene glycol diglycidylether-based epoxy cross-linking agent (“DENACOL” EX-830 produced byNagase ChemteX Corporation (molecular weight about 530, weight per epoxyequivalent 268, water solubility 100 percent)) serving as an epoxy-basedcross-linking agent was dissolved in water.

The coated monoaxially stretched film was grasped with clips, and wasled to a preheating zone. After drying was performed at 90° C., the filmwas continuously stretched by 4 times in a width direction in a heatingzone at 105° C., and furthermore, was subjected to a heat treatment in aheating zone at 225° C., so that a laminated film for a protective filmwas prepared, wherein crystalline orientation was completed. At thistime, the thickness of the base PET film was 50 μm, and the thickness ofthe laminated layer was 0.06 μm. The content of the water-solublecross-linking agent (B) in this laminated layer was 25 percent byweight. The results are shown in Table 2. Extremely excellent antistaticproperty, solvent resistance, and thermal shrinkage were exhibited and,in addition, excellent transparency was also exhibited.

Example 14

A laminated film for a protective film was prepared as in Example 13except that Coating solution A2 and Coating solution B6 were used inplace of the laminated layer-forming coating solution in Example 13,while the mixing ratio of Coating solution A2 to Coating solution B6 wascontrolled at 60/40 (weight ratio of solid). The content of thewater-soluble cross-linking agent (B) in this laminated layer was 40percent by weight. The results are also shown in Table 2. Extremelyexcellent transparency, antistatic property, solvent resistance, andthermal shrinkage were exhibited.

Example 15

A laminated film for a protective film was prepared as in Example 13except that a mixture of Coating solution A2 and Coating solution B6 wasused in place of the laminated layer-forming coating solution in Example13, while the ratio of Coating solution A2 to Coating solution B6 wascontrolled at 30/70 (weight ratio of solid). The content of thewater-soluble cross-linking agent (B) in this laminated layer was 70percent by weight. The results are also shown in Table 2. Extremelyexcellent transparency, antistatic property, solvent resistance, andthermal shrinkage were exhibited.

Example 16

A laminated film for a protective film was prepared as in Example 13except that Coating solution A2 and Coating solution B6 were used as thelaminated layer-forming coating solution in Example 13, while the mixingratio of Coating solution A2 to Coating solution B6 was controlled at15/85 (weight ratio of solid). The content of the water-solublecross-linking agent (B) in this laminated layer was 85 percent byweight. The results are also shown in Table 2. Extremely excellenttransparency, antistatic property, solvent resistance, and thermalshrinkage were exhibited.

Example 17

PET pellets (intrinsic viscosity 0.65 dl/g) containing substantially noparticle were adequately vacuum-dried and, thereafter, were supplied toan extruder. The pellets were melted at 280° C., and were extruded froma T-die into the shape of a sheet. The resulting sheet was wound arounda mirror-finished casting drum having a surface temperature of 20° C. bythe use of an electrostatic casting method, followed by cooling andsolidifying. The resulting non-stretched film was heated to 88° C., andwas stretched by 3.3 times in a longitudinal direction, so that amonoaxially stretched film was prepared. This film was subjected to acorona discharge treatment in air, and the treated surface was coatedwith a laminated layer-forming coating solution described below.

“Laminated Layer-Forming Coating Solution”

A laminated layer-forming coating solution was prepared by mixing thefollowing Coating solution A2 and Coating solution B4 at a ratio ofCoating solution A2/Coating solution B4=25/75 on a weight of solidbasis.

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution B4:

a water-based coating solution in which ethylene-polyethylene glycoldiglycidyl ether-based epoxy cross-linking agent (“DENACOL” EX-810produced by Nagase ChemteX Corporation (molecular weight about 230,weight per epoxy equivalent 113, water solubility 100 percent)) servingas an epoxy-based cross-linking agent was dissolved in water.

The coated monoaxially stretched film was grasped with clips, and wasled to a preheating zone. After drying was performed at 90° C., the filmwas continuously stretched by 4 times in a width direction in a heatingzone at 105° C., and furthermore, was subjected to a heat treatment in aheating zone at 225° C., so that a laminated film for a protective filmwas prepared, wherein crystalline orientation was completed. At thistime, the thickness of the base PET film was 50 μm, and the thickness ofthe laminated layer was 0.06 μm. The content of the water-solublecross-linking agent (B) in this laminated layer was 75 percent byweight. The results are shown in Table 2. Extremely excellenttransparency, antistatic property, solvent resistance, and thermalshrinkage were exhibited.

Example 18

A laminated film for a protective film was prepared as in Example 13except that a mixture of Coating solution A2 and Coating solution B5were used in place of the laminated layer-forming coating solution inExample 13, while the ratio of Coating solution A2 to Coating solutionB5 was controlled at 40/60 (weight ratio of solid), and the thickness ofthe laminated layer was controlled at 0.03 μm. The content of thewater-soluble cross-linking agent (B) in this laminated layer was 60percent by weight. The results are also shown in Table 2. Extremelyexcellent solvent resistance and thermal shrinkage were exhibited and,in addition, excellent transparency and antistatic property wereexhibited as well.

“Laminated Layer-Forming Coating Solution”

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution B5:

a water-based coating solution in which methylol type melaminecross-linking agent (“NIKALAC” MW12LF produced by SANWA CHEMICAL CO.,LTD. (molecular weight about 340)) serving as a melamine-basedcross-linking agent was dissolved in water.

Comparative Example 6

A laminated film for a protective film was prepared as in Example 13except that the following laminated layer-forming coating solution wasused in place of the laminated layer-forming coating solution in Example13. The content of the water-soluble cross-linking agent (B) in thislaminated layer was 0 percent by weight. The results are also shown inTable 2. Whitening of the coating film occurred so that the transparencywas significantly poor, no solvent resistance was exhibited, and anextremely poor antistatic property was exhibited.

“Laminated Layer-Forming Coating Solution”

The following Coating solution A2 was used alone as the laminatedlayer-forming coating solution.

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Comparative Example 7

A laminated film for a protective film was prepared as in Example 13except that a laminated layer-forming coating solution having thefollowing composition was used in place of the laminated layer-formingcoating solution in Example 13. The water solubility of thewater-soluble cross-linking agent in this laminated layer was 64 percentand, therefore, the water-soluble cross-linking agent was out of therange of the cross-linking agent (B). The results are also shown inTable 2. Whitening of the coating film occurred so that the transparencywas poor, no solvent resistance was exhibited, and an extremely poorantistatic property was exhibited.

“Laminated Layer-Forming Coating Solution”

A laminated layer-forming coating solution was prepared by mixing thefollowing Coating solution A2 and Coating solution B7 at a ratio ofCoating solution A2/Coating solution B7=90/10 on a weight of solidbasis.

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution B7:

a water-based coating solution composed of glycerol polyglycidylether-based epoxy cross-linking agent (“DENACOL” EX-314 produced byNagase ChemteX Corporation (molecular weight about 320, weight per epoxyequivalent 144, water solubility 64 percent)) serving as an epoxy-basedcross-linking agent.

Comparative Example 8

A laminated film for a protective film was prepared as in Example 13except that a mixture of Coating solution A2 and Coating solution B6 wasused as the laminated layer-forming coating solution in Example 13,while the ratio of Coating solution A2 to Coating solution B6 wascontrolled at 95/5 (weight ratio of solid). The content of thewater-soluble cross-linking agent (B) in this laminated layer was 5percent by weight. The results are also shown in Table 2. Whitening ofthe coating film occurred so that the transparency was poor, no solventresistance was exhibited, and the antistatic property was inadequate.

Comparative Example 9

A laminated film for a protective film was prepared as in Example 13except that a mixture of Coating solution A2 and Coating solution B6 wasused as the laminated layer-forming coating solution in Example 13,while the ratio of Coating solution A2 to Coating solution B6 wascontrolled at 8/92 (weight ratio of solid). The content of thewater-soluble cross-linking agent (B) in this laminated layer was 92percent by weight. The results are also shown in Table 2. The coatingfilm exhibited good transparency and solvent resistance, but exhibitedan extremely poor antistatic property.

Comparative Example 10

A laminated film for a protective film was prepared as in Example 13except that a laminated layer-forming coating solution having thefollowing composition was used in place of the laminated layer-formingcoating solution in Example 13. The water solubility of thewater-soluble cross-linking agent in this laminated layer was 48 percentand, therefore, the water-soluble cross-linking agent was out of therange of the cross-linking agent (B). The results are also shown inTable 2. Whitening of the coating film occurred so that the transparencywas poor, no solvent resistance was exhibited, and an extremely poorantistatic property was exhibited.

“Laminated Layer-Forming Coating Solution”

A laminated layer-forming coating solution was prepared by mixing thefollowing Coating solution A2 and Coating solution B8 at a ratio ofCoating solution A2/Coating solution B8=25/75 on a weight of solidbasis. Since, the coating solution included many aggregates andinsoluble matters, a film was coated with the coating solution filtratedwith a filter.

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution B8:

a water-based coating solution composed of sorbitol polyglycidylether-based epoxy cross-linking agent (“DENACOL” EX-611 produced byNagase ChemteX Corporation (molecular weight about 630, weight per epoxyequivalent 167, water solubility 48 percent)) serving as an epoxy-basedcross-linking agent.

Comparative Example 11

A laminated film for a protective film was prepared as in Example 13except that a laminated layer-forming coating solution having thefollowing composition was used in place of the laminated layer-formingcoating solution in Example 13. The results are also shown in Table 2.In the present comparative example, since the composition (A) composedof a polythiophene and/or a derivative thereof and a polyanion was notused, significant humidity dependence was exhibited, and in particular,the antistatic property was extremely poor at a low humidity.Furthermore, whitening of the coating film occurred so that thetransparency was poor, and no solvent resistance was exhibited.

“Laminated Layer-Forming Coating Solution”

A laminated layer-forming coating solution was prepared by mixing thefollowing Coating solution D2 and Coating solution B6 at a ratio ofCoating solution D2/Coating solution B6=50/50 on a weight of solidbasis.

Coating Solution D2:

a water-based coating solution in which sodium polystyrenesulfonate(weight average molecular weight: 500,000) was dissolved in water.

Coating Solution B6:

a water-based coating solution in which a polyethylene glycol diglycidylether-based epoxy cross-linking agent (“DENACOL” EX-830 produced byNagase ChemteX Corporation (molecular weight about 530, weight per epoxyequivalent 268, water solubility 100 percent)) serving as an epoxy-basedcross-linking agent was dissolved in water.

Comparative Example 12

A laminated film for a protective film was prepared as in Example 13except that a laminated layer-forming coating solution having thefollowing composition was used in place of the laminated layer-formingcoating solution in Example 13. The content of the water-solublecross-linking agent (B) in this laminated layer was 0 percent by weight.The results are also shown in Table 2. Whitening of the coating filmoccurred so that the transparency was poor, no solvent resistance wasexhibited, and the antistatic property was inadequate.

“Laminated Layer-Forming Coating Solution”

A laminated layer-forming coating solution was prepared by mixing thefollowing Coating solution A2 and Coating solution C2 at a ratio ofCoating solution A2/Coating solution C2=80/20 on a weight of solidbasis.

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution C2:

a water-based dispersion (so-called “latex”-like coating solution, watersolubility: 1 percent or less) in which a granular acrylic resin (glasstransition temperature: 42° C.) composed of the following copolymercomposition was dispersed in water.

Copolymer components methyl methacrylate 62 mole percent ethyl acrylate35 mole percent acrylic acid  1 mole percent N-methylolacrylamide  2mole percent

Example 19

An acrylic adhesive containing butyl acrylate, 2-ethylhexyl acrylate,and ethylene-acrylic acid was applied by a gravure coating method to thesurface opposite to the surface provided with the laminated layer of thelaminated film for a protective film prepared in Example 15 in orderthat an adhesive layer having a thickness after drying andsolidification of 10 μm was formed and, thereby, a protective film wasprepared.

The protective film was affixed to a polarizer serving as a displaycomponent. As a result, very excellent transparency was exhibited, anexcellent antistatic property was exhibited on the surface side and,therefore, for example, no dirt was adhered. The adhesive partiallyadhered to end portions and the like due to lying off of the adhesiveapplied in the step of processing the adhesive layer was able to bereadily wiped off with a gauze impregnated with ethanol, and no changewas observed in outward appearance.

TABLE 2 Content of water-soluble cross-linking Laminated Antistaticproperty Laminated layer agent (B) layer Relative Relative SolventThermal composition (percent by thickness Haze humidity humidityresistance shrinkage Coating solution weight) (μm) (%) 65% 25% 1 2 3 (%)Example 13 A2/B6 25 0.06 2.5 6 × 10⁶ 6 × 10⁶ 4 4 4 0.7 Example 14 A2/B640 0.06 1.8 8 × 10⁶ 8 × 10⁶ 4 4 5 0.5 Example 15 A2/B6 70 0.06 1.7 4 ×10⁷ 4 × 10⁷ 5 5 5 0.3 Example 16 A2/B6 85 0.06 1.2 1 × 10⁸ 1 × 10⁸ 5 5 50.3 Example 17 A2/B4 75 0.06 0.6 1 × 10⁷ 1 × 10⁷ 5 5 5 0.3 Example 18A2/B5 60 0.03 3.8 6 × 10⁹ 6 × 10⁹ 4 4 4 0.8 Comparative A2 0 0.06 13.2 6× 10¹⁴ 8 × 10¹⁴ 1 1 2 1.1 example 6 Comparative A2/B7 10 0.06 8.2 2 ×10¹³ 2 × 10¹³ 2 2 2 1.0 example 7 Comparative A2/B6 5 0.06 8.7 5 × 10¹²5 × 10¹² 1 1 2 1.1 example 8 Comparative A2/B6 92 0.06 1.0 1 × 10¹⁵ 2 ×10¹⁵ 4 4 5 1.1 example 9 Comparative A2/B8 75 0.06 10.5 7 × 10¹³ 7 ×10¹³ 2 3 3 1.1 example 10 Comparative D2/B6 50 0.1 19.0 8 × 10¹² 5 ×10¹⁴ 1 1 1 1.4 example 11 Comparative A2/C2 0 0.06 13.0 6 × 10¹² 8 ×10¹² 2 1 2 1.4 example 12

Example 20

PET pellets (intrinsic viscosity 0.63 dl/g) containing 0.01 percent byweight of aggregated silica having an average particle diameter of 0.7μm and 0.006 percent by weight of aggregated silica having an averageparticle diameter of 1.4 μm were adequately vacuum-dried and,thereafter, were supplied to an extruder. The pellets were melted at285° C., and were extruded from a T-die into the shape of a sheet. Theresulting sheet was wound around a mirror-finished casting drum having asurface temperature of 25° C. by the use of an electrostatic castingmethod, followed by cooling and solidifying. The resulting non-stretchedfilm was heated to 89° C., and was stretched by 3.3 times in alongitudinal direction, so that a monoaxially stretched film wasprepared. This film was subjected to a corona discharge treatment inair, and the treated surface was coated with a laminated layer-formingcoating solution described below.

“Laminated Layer-Forming Coating Solution”

A laminated layer-forming coating solution was prepared by mixing thefollowing Coating solution A2 and Coating solution B6 at a ratio ofCoating solution A2/Coating solution B6=25/75 on a weight of solidbasis.

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution B6:

a water-based coating solution in which a polyethylene glycol diglycidylether-based epoxy cross-linking agent (“DENACOL” EX-830 produced byNagase ChemteX Corporation (molecular weight about 530, weight per epoxyequivalent 268, water solubility 100 percent)) serving as an epoxy-basedcross-linking agent was dissolved in water.

The coated monoaxially stretched film was grasped with clips, and wasled to a preheating zone. After drying was performed at 90° C., the filmwas continuously stretched by 4.1 times in a width direction in aheating zone at 105° C., and furthermore, was subjected to a heattreatment in a heating zone at 225° C., so that a laminated film servingfor a cover tape was prepared, wherein crystalline orientation wascompleted. At this time, the thickness of the base PET film was 35 μm,and the thickness of the laminated layer was 0.05 μm. The content of thewater-soluble cross-linking agent (B) in this laminated layer was 75percent by weight. The results are shown in Table 3. Extremely excellenttransparency, antistatic property, and scratch resistance wereexhibited.

Example 21

A laminated film for a cover tape was prepared as in Example 20 exceptthat a mixture of Coating solution A2 and Coating solution B6 was usedas the laminated layer-forming coating solution in Example 20 while theratio of Coating solution A2 to Coating solution B6 was controlled at75/25 (weight ratio of solid), and the thickness of the laminated layerwas controlled at 0.03 μm. The content of the water-solublecross-linking agent (B) in this laminated layer was 25 percent byweight. The results are also shown in Table 3. Extremely excellenttransparency, antistatic property, and scratch resistance wereexhibited.

Example 22

A laminated film for a cover tape was prepared as in Example 20 exceptthat a mixture of Coating solution A2 and Coating solution B6 was usedas the laminated layer-forming coating solution in Example 20 while theratio of Coating solution A2 to Coating solution B6 was controlled at50/50 (weight ratio of solid). The content of the water-solublecross-linking agent (B) in this laminated layer was 50 percent byweight. The results are also shown in Table 3. Extremely excellenttransparency, antistatic property, and scratch resistance wereexhibited.

Example 23

A laminated film for a cover tape was prepared as in Example 20 exceptthat a mixture of the following Coating solution A2 and Coating solutionB1 was used in place of the laminated layer-forming coating solution inExample 20, while the ratio of Coating solution A2 to Coating solutionB1 was controlled at 25/75 (weight ratio of solid). The content of thewater-soluble cross-linking agent (B) in this laminated layer was 75percent by weight. The results are also shown in Table 3. Extremelyexcellent transparency, antistatic property, and scratch resistance wereexhibited.

“Laminated Layer-Forming Coating Solution”

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution B1:

a water-based coating solution in which polyglycerol polyglycidylether-based epoxy cross-linking agent (“DENACOL” EX-512 produced byNagase ChemteX Corporation (molecular weight about 630, weight per epoxyequivalent 168, water solubility 100 percent)) serving as an epoxy-basedcross-linking agent was dissolved in water.

Example 24

A laminated film for a cover tape was prepared as in Example 20 exceptthat a mixture of the following Coating solution A2 and Coating solutionB4 was used in place of the laminated layer-forming coating solution inExample 20, while the ratio of Coating solution A2 to Coating solutionB4 was controlled at 30/70 (weight ratio of solid). The content of thewater-soluble cross-linking agent (B) in this laminated layer was 70percent by weight. The results are also shown in Table 3. Extremelyexcellent transparency, antistatic property, and scratch resistance wereexhibited.

“Laminated Layer-Forming Coating Solution”

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution B4:

a water-based coating solution in which ethylene•polyethylene glycoldiglycidyl ether-based epoxy cross-linking agent (“DENACOL” EX-810produced by Nagase ChemteX Corporation (molecular weight about 230,weight per epoxy equivalent 113, water solubility 100 percent)) servingas an epoxy-based cross-linking agent was dissolved in water.

Comparative Example 13

A PET film for a cover tape was prepared in Example 20 except that thelaminated layer-forming coating solution was not applied and, thereby,no laminated layer was provided. The results are also shown in Table 3.An extremely poor antistatic property was exhibited.

Comparative Example 14

A laminated film for a cover tape was prepared as in Example 20 exceptthat the following laminated layer-forming coating solution was used inplace of the laminated layer-forming coating solution in Example 20. Thecontent of the water-soluble cross-linking agent (B) in this laminatedlayer was 0 percent by weight. The results are also shown in Table 3.The coating film tended to be whitened and scratched, and an extremelypoor antistatic property was exhibited.

“Laminated Layer-Forming Coating Solution”

The following Coating solution A2 was used alone as the laminatedlayer-forming coating solution.

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Comparative Example 15

A laminated film for a cover tape was prepared as in Example 20 exceptthat the following laminated layer-forming coating solution was used inplace of the laminated layer-forming coating solution in Example 20. Thewater solubility of the water-soluble cross-linking agent (B) in thislaminated layer was 78 percent and, therefore, the water-solublecross-linking agent was out of the range of the cross-linking agent (B).The results are also shown in Table 3. The coating film tended to bewhitened and scratched, and an extremely poor antistatic property wasexhibited.

“Laminated Layer-Forming Coating Solution”

A laminated layer-forming coating solution was prepared by mixing thefollowing Coating solution A2 and Coating solution B9 at a ratio ofCoating solution A2/Coating solution B9=30/70 on a weight of solidbasis.

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution B9:

a water-based coating solution in which sorbitol polyglycidylether-based epoxy cross-linking agent (“DENACOL” EX-614 produced byNagase ChemteX Corporation (molecular weight about 550, weight per epoxyequivalent 167, water solubility 78 percent)) serving as an epoxy-basedcross-linking agent was dissolved in water.

Comparative Example 16

A laminated film for a cover tape was prepared as in Example 20 exceptthat the following laminated layer-forming coating solution was used inplace of the laminated layer-forming coating solution in Example 20. Thecontent of the water-soluble cross-linking agent (B) in this laminatedlayer was 92 percent by weight. The results are also shown in Table 3.An extremely poor antistatic property was exhibited.

“Laminated Layer-Forming Coating Solution”

A laminated layer-forming coating solution was prepared by mixing thefollowing Coating solution A2 and Coating solution B4 at a ratio ofCoating solution A2/Coating solution B4=8/92 on a weight of solid basis.

Coating Solution A2:

a water-based coating solution (“DENATRON” #5002RZ produced by NagaseChemteX Corporation) in which a polyester resin and a complex composedof polyethylenedioxythiophene/polystyrenesulfonic acid were dispersed inwater.

Coating Solution B4:

a water-based coating solution in which ethylene-polyethylene glycoldiglycidyl ether-based epoxy cross-linking agent (“DENACOL” EX-810produced by Nagase ChemteX Corporation (molecular weight about 230,weight per epoxy equivalent 113, water solubility 100 percent)) servingas an epoxy-based cross-linking agent was dissolved in water.

Comparative Example 17

A laminated film for a cover tape was prepared as in Example 20 exceptthat the following laminated layer-forming coating solution was used inplace of the laminated layer-forming coating solution in Example 20. Thecontent of the water-soluble cross-linking agent (B) in this laminatedlayer was 0 percent by weight. The results are also shown in Table 3. Inthe present comparative example, since the composition (A) composed of apolythiophene and/or a derivative thereof and a polyanion and thewater-soluble cross-linking agent (B) were not used, significanthumidity dependence was exhibited, and in particular, a poor antistaticproperty was exhibited at a low humidity, and no water resistance wasexhibited.

“Laminated Layer-Forming Coating Solution”

A laminated layer-forming coating solution was prepared by mixing thefollowing Coating solution D3 and Coating solution C2 at a ratio ofCoating solution D3/Coating solution C2=20/80 on a weight of solidbasis.

Coating Solution D3: a water-based coating solution in which ammoniumpolystyrenesulfonate (weight average molecular weight: 10,000) wasdissolved in water.

Coating Solution C2: a water-based dispersion (so-called “latex”-likecoating solution, water solubility: 1 percent or less) in which agranular acrylic resin (glass transition temperature: 42° C.) composedof the following copolymer composition was dispersed in water.

Copolymer components methyl methacrylate 62 mole percent ethyl acrylate35 mole percent acrylic acid  1 mole percent N-methylolacrylamide  2mole percent

Example 25

An acrylic adhesive containing butyl acrylate, 2-ethylhexyl acrylate,and ethylene-acrylic acid was applied by a gravure coating method to thesurface opposite to the surface provided with the laminated layer of thelaminated film for a cover tape prepared in Example 24 in order that anadhesive layer having a thickness after drying and solidification of 5μm was formed and, thereby, a cover tape was prepared.

The static voltage was measured with an honestmeter. The static voltagewas on the order of 20 V when the voltage was applied, and the staticvoltage attenuated to 0 V after a lapse of 1 second from termination ofthe application. A cover tape having extremely excellent antistaticproperty was able to be prepared.

Example 26

The surface opposite to the surface provided with the laminated layer ofthe laminated film for a cover tape prepared in Example 24 was subjectedto a corona discharge treatment in air at a treatment intensity of 30W·min/m2, a polyethylene film of 16 μm in thickness was heat-laminatedon the treated surface and, thereby, a cover tape was prepared.

The static voltage was measured with an honestmeter. The static voltagewas on the order of 20 V when the voltage was applied, and the staticvoltage attenuated to 0 V after a lapse of 1 second from termination ofthe application. A cover tape having extremely excellent antistaticproperty was able to be prepared.

Comparative Example 18

An adhesive layer-forming coating solution composed of the followingcomposition was applied by a gravure coating method to the surfaceopposite to the surface provided with the laminated layer of thelaminated film for a cover tape prepared in Example 24 in order that anadhesive layer having a thickness after drying and solidification of 5μm was formed and, thereby, a cover tape was prepared. After heatlamination of the caver tape and a carrier tape was performed, thepeeling was not stable because, for example, peeling occurredspontaneously. The contact angle of water on the surface after beingpeeled off was measured, and was 62 degrees.

“Adhesive Layer-Forming Coating Solution”

An adhesive layer-forming coating solution was prepared by mixing thefollowing Coating solution E1 and Coating solution F1 at a ratio ofCoating solution E1/Coating solution F1=90/10 on a weight of solidbasis.

Coating Solution E1: a water-based coating solution in whichpolyethylene resin emulsion having an emulsion particle diameter ofabout 0.5 μm was dispersed in water

Coating solution F1: a water-based coating solution in whichN,N-bis(2-hydroxyethyl)laurylamine serving as a nonionic antistaticagent was dispersed in water

Example 27

A plastic sheet in which 15 percent by weight of carbon black wasincorporated into a polystyrene resin film and which had a thickness of3 mm and a width of 25 mm was provided with square recessed-portionshaving a size of 16 mm×16 mm and a depth of 1.5 mm at spacings of 2 cmwith a molding machine and, thereby, a carrier tape was prepared. ICchips were encapsulated into the resulting carrier tape, the surface, onwhich the polyester film was laminated, of the cover tape prepared inExample 25 and the carrier tape were heat-laminated and, thereby, acarrier package was prepared.

The resulting carrier package had excellent visibility of the portionencapsulating electronic components from the cover tape side, and thestatic voltage measured with an honestmeter was 0 V after the cover tapewas peeled off. The contact angle of water on the surface after thecover tape was peeled off was 100 degrees, and an excellent peelingstability was exhibited.

TABLE 3 Content of water-soluble cross-linking Laminated Antistaticproperty Laminated layer agent (B) layer Relative Relative composition(percent by thickness Haze humidity humidity Scratch Coating solutionweight) (μm) (%) 65% 25% resistance 2 Example 20 A2/B6 75 0.05 1.0 7 ×10⁷ 7 × 10⁷ 5 Example 21 A2/B6 25 0.03 2.4 6 × 10⁶ 7 × 10⁶ 5 Example 22A2/B6 50 0.05 1.8 1 × 10⁷ 1 × 10⁷ 5 Example 23 A2/B1 75 0.05 1.7 2 × 10⁸2 × 10⁸ 5 Example 24 A2/B4 70 0.05 1.0 1 × 10⁷ 1 × 10⁷ 5 Comparativeexample 13 No laminated layer 1.0 8 × 10¹⁴ 1 × 10¹⁵ 5 Comparativeexample 14 A2 0 0.05 13.0 6 × 10¹⁴ 8 × 10¹⁴ 2 Comparative example 15A2/B9 0 0.05 10.3 8 × 10¹³ 9 × 10¹³ 3 Comparative example 16 A2/B4 920.05 1.0 1 × 10¹⁵ 3 × 10¹⁵ 5 Comparative example 17 D3/C2 0 0.08 1.2 5 ×10¹⁰ 1 × 10¹³ 2

INDUSTRIAL APPLICABILITY

The laminated film has an extremely excellent antistatic property and,therefore, is very useful as a base film for various purposes. Thelaminated film can be widely used as various base films serving for,e.g., magnetic recording materials, electrically insulating materials,insulating tapes, electrical materials, optics, graphics, cards,transfer foils, ribbons, evaporation, packaging, capacitors, and varioustapes.

Furthermore, the laminated film for protective film and the protectivefilm can be primarily used for protecting surfaces during processing andmounting of polarizers and the like used for e.g., liquid crystaltelevisions, displays for car navigation, liquid crystal displays ofcellular phones, and computer displays.

The laminated film for cover tape can be used for cover tapes andcarrier packages.

1. A laminated film in which a laminated layer comprising composition(A) and epoxy-based cross-linking agent (B) is laminated on at least onesurface of a thermoplastic resin film, wherein the 1) laminated layercomprises at least 70 percent by weight of both composition (A) andepoxy-based cross-linking agent (B) based on the total weight of thelaminated layer, 2) epoxy-based cross-linking agent (B) is 40 to 85percent based on the total weight of the laminated layer and provides ahaze value of 1.8% or less, 3) composition (A) is a compositioncomprising a polythiophene and a polyanion or a composition comprising apolythiophene derivative and a polyanion, 4) epoxy-based cross-linkingagent (B) has a molecular weight of 800 or less, 5) laminated layer hasa sea-island structure in which the epoxy-based cross-linking agent (B)is present in the composition (A), 6) epoxy-based cross-linking agent(B) is a water-soluble cross-linking agent and 7) laminated layer has asurface resistivity (23° C. relative humidity 65 percent) of 3×10⁸ Ω/□or less.
 2. The laminated film according to claim 1, wherein thecomposition (A) includes a composition comprising a polythiophene and apolyanion and a composition comprising a polythiophene derivative and apolyanion.
 3. The laminated film according to claim 1, wherein apolyester resin is contained in the laminated layer.
 4. The laminatedfilm according to claim 1, wherein the composition (A) is a compositioncomprising polyethylenedioxythiophene and polystyrenesulfonic acid. 5.The laminated film according to claim 1, wherein the thermoplastic resinfilm comprises a polyethylene terephthalate film or apolyethylene-2,6-naphthalate film.
 6. A protective film in which anadhesive layer is provided on at least one surface of the laminated filmaccording to claim
 1. 7. A cover tape in which a polyolefin-based resinlayer and/or an adhesive layer of 0.5 to 20 μm in thickness is providedon at least one surface of the laminated film according to claim
 1. 8. Acarrier package in which a carrier tape is laminated on at least onesurface of the laminated film according to claim
 1. 9. The laminatedfilm according to claim 1, wherein the surface resistivity (23° C.,relative humidity 25%) is 4×10⁸ Ω/□ or less.
 10. The laminated filmaccording to claim 1, wherein a thickness of the laminated layer is 70nm or less.
 11. A method for manufacturing a laminated film, comprisingapplying a coating solution containing a composition (A) and across-linking agent (B) to at least one surface of a thermoplastic resinfilm directly to form a laminated layer, followed by drying, stretchingand heat-treating, wherein the 1) laminated layer comprises at least 70percent by weight of both composition (A) and epoxy-based cross-linkingagent (B) based on the total weight of the laminated layer, 2)epoxy-based cross-linking agent (B) is 40 to 85 percent based on thetotal weight of the laminated layer and provides a haze value of 1.8% orless, 3) composition (A) is a composition comprising a polythiophene anda polyanion or a composition comprising a polythiophene derivative and apolyanion, 4) epoxy-based cross-linking agent (B) has a molecular weightof 800 or less, 5) laminated layer has a sea-island structure in whichthe epoxy-based cross-linking agent (B) is present in the composition(A), 6) epoxy-based cross-linking agent (B) is a water solublecross-linking agent and 7) laminated layer has a surface resistivity(23° C., relative humidity 65 percent) of 3×10⁸ Ω/□ or less.
 12. Thelaminated film according to claim 11, wherein the surface resistivity(23° C., relative humidity 25%) is 4×10⁸ Ω/□ or less.
 13. The method formanufacturing a laminated film according to claim 11, wherein athickness of the laminated layer is 70 nm or less.
 14. A laminated filmfor a protective film, in which a laminated layer comprising (A) andepoxy-based cross-linking agent (B) is laminated on at least one surfaceof a thermoplastic resin film wherein the 1) laminated layer comprisesat least 70 percent by weight of both composition (A) and epoxy-basedcross-linking agent (B) based on the total weight of the laminatedlayer, 2) epoxy-based cross-linking agent (B) is 40 to 85 percent basedon the total weight of the laminated layer and provides a haze value of1.8% or less, 3) composition (A) is a composition comprising apolythiophene and a polyanion or a composition comprising apolythiophene derivative and polyanion, 4) epoxy-based cross-linkingagent (B) has a molecular weight of 800 or less, 5) laminated layer hasa sea-island structure in which the epoxy-based cross-linking agent (B)is presented in the composition (A), 6) epoxy-based cross-linking agent(B) is a water-soluble cross-linking agent and 7) laminated layer has asurface resistivity (23° C., relative humidity 65 percent) of 3×10⁸ Ω/□or less.
 15. The laminated film according to claim 14, wherein thethermal shrinkage is −0.5 percent or more and 1 percent or less after alapse of 30 minutes at 150° C.
 16. A protective film in which anadhesive layer is provided on at least one surface of the laminated filmaccording to claim
 14. 17. The laminated film according to claim 14,wherein the surface resistivity (23° C., relative humidity 25%) is 4×10⁸Ω/□ or less.
 18. The laminated film for a protective film according toclaim 14, wherein a thickness of the laminated layer is 70 nm or less.19. A laminated film for a cover tape, in which a laminated layercomprising composition (A) and epoxy-based cross-linking agent (B) islaminated on at least one surface of a thermoplastic resin film, whereinthe 1) laminated layer comprises at least 70 percent by weight of bothcomposition (A) and epoxy-based cross-linking agent (B) based on thetotal weight of the laminated layer, 2) epoxy-based cross-linking agent(B) is 40 to 85 percent based on the total weight of the laminated layerand provides a haze value of 1.8% or less, 3) composition (A)is acomposition comprising a polythiophene and a polyanion or a compositioncomprising a polythiophene derivative and a polyanion, 4) epoxy-basedcross-linking agent (B) has a molecular weight of 800 or less, 5)laminated layer has a sea-island structure in which the epoxy-basedcross-linking agent (B) is present in the composition (A), 6)epoxy-based cross-linking agent (B) is a water-soluble cross-linkingagent and 7) laminated layer has a surface resistivity (23° C., relativehumidity 65 percent) of 3×10⁸ Ω/□ or less.
 20. A cover tape in which apolyolefin-based resin layer and/or an adhesive layer of 0.5 to 20 μm inthickness is provided on at least one surface of the laminated filmserving for a cover tape according to claim
 19. 21. The cover tapeaccording to claim 20, wherein the polyolefin-based resin is apolyethylene resin, and the contact angle of water on the surface of thepolyolefin-based resin layer and/or an adhesive layer is 80 to 110degrees.
 22. A cater package in which a polyolefin-based resin layerand/or an adhesive layer of 0.5 to 20 μm in thickness is provided on atleast one surface of the laminated film serving for a cover tapeaccording to claim 19, and a carrier tape is laminated on thepolyolefin-based resin layer and/or an adhesive layer.
 23. The laminatedfilm according to claim 19, wherein the resistivity (23° C., relativehumidity 25%) is 4×10⁸ Ω/□ or less.
 24. The laminated film for a covertape according to claim 19, wherein a thickness of the laminated layeris 70 nm or less.
 25. A laminated film for a transfer foil, in which alaminated layer comprising composition (A) and epoxy-based cross-linkingagent (B) is laminated on at least one surface of a thermoplastic resinfilm wherein the 1) laminated layer comprises at least 70 percent byweight of both composition (A) and epoxy-based cross-linking agent (B)based on the total weight of the laminated layer, 2) epoxy-basedcross-linking agent (B) is 40 to 85 percent based on the total weight ofthe laminated layer by weight in the laminated layer and provides a hazevalue of 1.8% or less, 3) composition (A) is a composition comprising apolythiophene and a polyanion or a composition comprising apolythiophene derivate and a polyanion 4) epoxy-based cross-linkingagent (B) has a molecular weight of 800 or less, 5) laminated layer hasa sea-island structure in which the epoxy-based cross-linking agent (B)is presented in the composition (A), 6) epoxy-based cross-linking agent(B) is a water-soluble cross-linking agent and 7) laminated layer has asurface resistivity (23° C., relative humidity 65 percent of 3×10⁸ Ω/□or less.
 26. The laminated film according to claim 25, wherein thesurface resistivity (23° C., relative humidity 25%) is 4×10⁸ Ω/□ orless.
 27. The laminated film for a transfer foil according to claim 25,wherein a thickness of the laminated layer is 70 nm or less.